When information is organized in folders, files, menus, categories, etc., you can explain where a particular thing is by saying that it's "under" some heading.

For example:

• a photo that's in a folder called "Pictures" on your computer is "under 'Pictures'"
• the setting on your TV that controls its brightness might be "under 'Settings'"

You can also say that something is "filed under ___":

A: Where did we put last year's tax return?

B: I think it's filed under "Finances".