I wash and dry parsley and then process it - dry - through my Ninja until it is chopped very fine. Then I put it in a freezer bag and pop it in the freezer. When I need some, I just take the quantity I need from the bag.
I've never tried it with mint or basil but don't see why you couldn't. Actually, if I had excess basil I'd probably make pesto and freeze that. I buy pesto all the time at the grocery and don't use it fast enough so I put it in ice cube trays and freeze it.