How I download all my files from Drafts for iPhone? I made a lot of notes in Drafts and now want to have it on my Mac.

I have access to app by PhoneView but still can't find any text files. Also tried to contact the developer - no response.
Directly in the page you linked it's stated:

Flexible Output
Send tweets to Twitter, post to Facebook, compose and send email, SMS/Messages, create calendar events – or save drafts to Dropbox or Evernote

So you could just send these notes of yours through email or Dropbox, for instance.