Screenshot

The Screenshot menu is found in the standard Menu GUI screen in-game, allowing players to take pictures by clicking on "Take Screenshot". Alternatively, you can click "Print Screen" on most QWERTY keyboards to take a photo in-game, or anywhere on your computer.

Use in Making Decals
Taking screenshots is a very useful way to make Decals, as you can take screenshots, make any necessary edits, and then make an upload.

You can take as many screenshots as you want, but it's important that you only make the ones that you need.

You can also make photos of items with a transparent background by using a green screen brick.

Keeping for Memories
Just so you don't miss out on all the fun you've had in game with friends or any humorous event or awards you've gained, taking a screenshot of the moment would be one of the best decisions you can make as you can look back at your memories.

Reporting
Screenshots can be useful as proof against or for a claim. Most of the time, you can't report a player simply by the default report GUI in the menu screen. Writing a small summary of the report isn't exactly proof. Reporting to the creator of a game or on Roblox official contact email with a screenshot is the most you can do to show proof of anything inappropriate.