Does erase all contents and settings?

Erase all the info off my iPhone? And make it brand new?

Added (1). iPhone 5s

From the Home screen, tap Settings > General > Reset.
Tap Erase All content and Settings. If presented, enter the passcode.
Tap Erase iPhone. Allow several minutes for the reset and reboot processes to complete.

Yes. You also need to sign it out of iCloud and such before you reset it, for best results.