Best practices
Use a popover to expose a small amount of information or functionality.
Consider using popovers when you want more room for content.
Position popovers appropriately.
Use a Close button for confirmation and guidance only.
Always save work when automatically closing a nonmodal popover.
Show one popover at a time.
Don’t show another view over a popover.
When possible, let people close one popover and open another with a single click or tap.
Avoid making a popover too big.
Provide a smooth transition when changing the size of a popover.
Avoid using the word popover in help documentation.
Avoid using a popover to show a warning.
Platform considerations
iOS, iPadOS
Avoid displaying popovers in compact views.
macOS
- Attached popover
- Detached popover
Consider letting people detach a popover.
Make minimal appearance changes to a detached popover.
For the complete guidance, including worked examples and illustrations, see the canonical page: https://developer.apple.com/design/human-interface-guidelines/popovers