how do i add my DVD movie to itunes?

Unlike music CDs, which can be ripped to files and added to iTunes, commercial DVDs are copy protected and cannot be added to iTunes.

Or you can try ripping your DVD to MP4 then add to iTunes.

If your DVD is decrypted, Handbrake would work well. If it's a protected DVD, try MakeMKV+Handbrake (use MakeMKV to decrypt and output MKV, then use Handbrake to convert MKV to MP4). Or you can just try Free DVDAid. Good luck!