Setting this one up

Download it first — every app uploads from a local file, none of them take a URL. Then follow whichever applies:

• Microsoft Teams: Already in a meeting? Click the three dots (More) in the meeting toolbar, then Effects and avatars. Full Teams guide
• Zoom: Outside a meeting: click your profile picture, then Settings, then Background & Effects in the left rail. Full Zoom guide
• Google Meet: On the green room screen before you join, click the sparkle icon on your self-preview. Full Meet guide

Keep your head roughly centred and leave the punchline off to one side — the cutout pastes you into the middle of the frame, so anything directly behind your head is hidden for the entire call.