Click Share Screen, open the Advanced tab at the top of the picker, choose Portion of Screen and press Share. A green bordered rectangle lands on your desktop: drag inside it to move it, drag an edge or corner to resize it, and whatever is drawn inside it is what the room sees. The border turns orange while you drag, because Zoom pauses the feed rather than hauling viewers around your desktop with you. And because the box captures a rectangle of the display rather than an application, anything that moves over that rectangle, including another window, goes out live.
Placing and sizing the box, in order
The step people skip is the first one. Position the source window before you start the share, not after, because the region is anchored to display coordinates and does not follow an app around.
Park the source window where it will stay
Open the editor, the PDF, the terminal or the browser you want to show and snap it to a fixed position. Windows key plus Left or Right gives you geometry you can reproduce. Once you commit to a region, moving that window later walks your content straight out of the frame.
Open Share Screen and switch to the Advanced tab
The picker opens on Basic, which lists your displays and every open window. Portion of Screen is not there. The tab strip across the top of the picker separates Basic from Advanced. Click Advanced.
Select Portion of Screen, then press Share
It sits alongside options such as slides as a virtual background and content from a second camera. Selecting the tile starts nothing. The Share button in the corner of the picker does.
Drag the frame over what you want to show
Grab anywhere inside the rectangle and move it as a whole. It lives on one display: you can drag it to another monitor, but it cannot straddle two at once, so an application spread across a monitor boundary cannot be captured in a single region.
Size it with the edge and corner handles
Corners scale both axes, edges scale one. Zoom enforces a minimum size, so a very tight crop will simply stop shrinking. Leave a little slack around the content, because a region cut exactly to a window edge clips a scrollbar or a status line the moment anything reflows.
Release, confirm green, then check the outgoing picture
A green border means frames are going out. Look at your own thumbnail in the gallery, or better, join the meeting a second time from your phone and watch that. Your own desktop is the least reliable witness in the room.
Green means live, orange means paused
The colour of that border is the entire status indicator, and it has two causes that behave differently.
- Orange because you are dragging. The instant you grab the frame to move or resize it, Zoom stops transmitting. Viewers hold on the last frame they received. Let go and the border returns to green and the feed resumes by itself. Nothing to click.
- Orange because you pressed Pause Share. Same colour, same frozen frame for viewers, but this one does not clear itself. You have to click Resume Share in the meeting toolbar. If the border is orange and nobody is touching it, that is why.
The automatic pause exists for a good reason. Without it, every reposition would broadcast a smeared tour of your desktop, your taskbar and whatever else the rectangle swept across on the way. With it, the room sees a still image instead. That still image is also the problem: a frozen frame is indistinguishable from a crashed application or a dead connection. So if you have to re-aim the box mid answer, narrate it. One sentence, "I am moving the capture region, it will look frozen for a second", costs nothing and stops an interviewer wondering whether you are still there.
Resizing has a second effect worth knowing. Changing the rectangle changes the dimensions of the stream you are sending, so viewers can watch the picture rescale and, on a slow link, soften for a moment while the encoder settles. A big region spreads more pixels over the same bandwidth. A tight region gives sharper text. If your code has to be readable at the other end, crop to the code rather than sending the whole editor with its sidebars.
What viewers see when something moves over the region
This is where Portion of Screen surprises people, because it does not behave like a Window share at all. Region capture is a crop of the display, so occlusion is transmitted rather than filtered out. The right-hand column shows what a Window share would have done with the same event.
| What happens on your desktop | Portion of Screen: viewers get | Window share, for contrast |
|---|---|---|
| Another window is dragged over the region | Rendered live, cropped cleanly at the border. Half in and half out means viewers see exactly the half that overlaps. | Not rendered. The shared window keeps streaming its own pixels from underneath. |
| A notification toast fires | Rendered only if it lands inside the rectangle. Windows draws toasts at the bottom right, so a bottom-right region is the risky one. | Not rendered. A toast is a separate window. |
| A dialog opens, such as Save As or an update prompt | Rendered if it lands in the rectangle. Dialogs tend to open centred, which is often exactly where the region is. | Rendered only if it belongs to the shared window, and sometimes not even then. |
| Alt-Tab or Task View | Rendered if the switcher overlaps the region, thumbnails of every open window included. | Not rendered. |
| You move the source window | The content leaves the frame. Viewers watch your app slide out and the wallpaper slide in. The box does not follow it. | Nothing changes. Capture follows the window anywhere, including onto another monitor. |
| You scroll or type inside the source window | Rendered normally. The region stays put and the content moves under it, which is the mode working as designed. | Rendered normally. |
| You minimise the source window | Viewers see the desktop behind it, live, not a frozen frame. | The stream usually freezes on the last frame instead. |
| The green border itself, and Zoom's toolbar | Not sent. The border is drawn around the outside of the capture area, and the toolbar sits outside it too. | Not sent. |
| The screen locks or a screensaver starts | Whatever the display shows is what goes out. Set a generous lock timer before a long call. | Much the same risk in practice. |
One row is worth testing rather than trusting: placing the region directly over the Zoom meeting window itself. Zoom keeps its own interface out of its capture in the other share modes, but that is exactly the sort of behaviour that shifts between client versions, so try it on your machine before you build a layout around it.
When Portion of Screen is the wrong choice
In an interview, usually, it is. A Window share leaks less on every row above, survives you moving the window, and needs no aiming. Reach for a region only when the task genuinely calls for one: showing a single panel of a wide dashboard, putting two applications side by side inside one frame, cropping a very wide monitor down to something a viewer can read, or hiding a bookmarks bar you cannot otherwise remove from a browser window. If you are sharing an editor while you work through a problem with Code Copilot, a Window share is the steadier choice, because a region is one careless window drag away from broadcasting your desktop.
A sixty second solo test
Start a meeting with nobody in it. Join it again from your phone with the mic and camera off. Share exactly the region you plan to use on the day, then run the table: message yourself to fire a toast, press Alt-Tab, drag a window across the box, nudge the frame and watch the phone freeze while the border sits orange. A minute of that removes every assumption in this guide, including the ones that happen to be correct.
Where the overlay fits, and what it does not do
One thing genuinely stays out of all three modes. Windows lets a window be marked so the compositor strips it from any capture before an application ever receives the frame. OfferPilot AI uses that, so its overlay is absent from Portion of Screen, from Entire Screen, from a Window share, and from Teams, Meet, OBS and a plain screenshot, while staying visible on your own monitor. Not a blur and not a black rectangle: those pixels never enter the frame that gets encoded and sent. It is on every plan, free tier included.
The boundary matters as much as the capability, so here it is plainly. Capture exclusion covers screen sharing, screen recording and screenshots. It does nothing about a webcam, a lockdown browser that owns the machine, a proctor watching you in the room, eye tracking, or a phone propped up as a second camera. Eyes tracking off to one side read as eyes tracking off to one side on video, whatever is drawing them.
Limits of this guide
- It describes the Windows desktop client. The web client, macOS, a virtual machine or a remote desktop session route capture differently, and the Advanced tab does not always offer the same options there.
- Clients change. Tab labels, the minimum region size and whether the box reopens where you left it have all moved between releases. Re-run the solo test after a major update rather than trusting a screenshot from last year.
- Some rounds make all of this beside the point. In a proctored assessment inside a lockdown browser, the environment controls the machine and share-mode nuance stops mattering. OfferPilot AI is the wrong tool there, and we would rather say so than sell you something that does not apply. It is Windows 10 and 11 only, built for live calls and preparation.
Short version: park the window, Advanced tab, Portion of Screen, place the box before anyone is watching, and remember that orange means your audience is looking at a photograph.