If you want to make videos in Director Mode or use the in-game recorder, Rockstar will try to get you to tie your Youtube account to your Social Club account. This is not necessary.
Once you've completed your project and have Exported it your can find the rendered video (.mp4 file format) in the following location on your hard drive: Users\%USER%\AppData\Local\Rockstar Games\GTA V\videos\rendered
Do with the file what you will.