I deleted a file that lets me take picture and videos, and play music, help me!!!

[Elie Barbar]

I have an android and I deleted one of those files that come with the phone that are something like "com.android.app.system" and stuff like that, I think it was called "android.media" or "media. android" I can't remember!! Can someone tell me the name of the file and how can I restore it? I formatted my phone which means now I can't restore any files!!! I really wanna fix it without having to call the company or something! Thank you.