Deleted photos and videos are moved to the Recently Deleted album.

In the photos app, select the Albums, then swipe up until you see the Recently Deleted Folder. This is a step by step guide:

Delete or hide photos and videos on iPhone - Apple Support

Photos will remain in the Recently Deleted folder for 30 days. If it has been longer than that or they are deleted from the Recently Deleted folder, then they have been removed permanently. If there is no Recently Deleted folder, then it has been longer than 30 days or the photos have already been deleted from the folder.

Mac Jim ID wrote: In the photos app, select the Albums, then swipe up until you see the Recently Deleted Folder.

As in the guide Mac Jim ID linked, the next step is to select (tap on) the picture you want to restore, and a button labeled "Recover" will appear. Choosing Recover will remove the picture from "Recently Deleted" and put it back in any albums it was originally. [ Choosing "Delete" erases the picture forever. This is often BAD ]