how can i send a client a document and get $$$

Hello,i have a small document editing business for past few years i have been sending the project back to the client watermarked. How ever last couple of weeks i have had sp many orders not get picked up i thought they figured out how to remove watermark so i put password then clients would not return to pick up projeect i workrf on all day  for example this Monday i had 7 orders and only 1 came back to pick up and pay . I do not want to pre charge clients is there a sade way where i can get like a $5 or $10 dollar deposit till work is done and when they return it will go twords paymeant i just dont want them to think im here to run off with there $$ IS THERE A SOLUTION TI WHERE WE ARE BOTH SAFE ANY SUGGESTIONS PLEASE THANK YOU DEEZ