What's the easiest way to add frosting (privacy) to glass shower door?

Etch it with etching paint.

They sell film that looks like frosted glass. You can get it online or at home improvement stores. Comes in a roll. I have an actual window that looks outside in my shower. Didn't want to give my neighbors a show, so that's what I did. They have self adhesive rolls of it, but mine is not the adhesive kind. You use water and a squeegee to stick it. I've had it on the window for about a year and it hasn't fallen off. No one really ever touches the window I used it on though. I'm not sure if the constant opening and closing of a shower for wood loosen it or not. Maybe check reviews online before buying a product. I think I got mine on Amazon, but I'm not 100% sure.

Hang a shower curtain on the outside of the shower doors. Fast, cheap, easy and private

I agree with Amy. I’ve used the same film from Amazon on a window in the shower and on an all glass exterior patio door and both are holding up well.

Home Depot and most home improvement stores sell film products specifically made for this. You can purchase rolls or sheets that looks like frosted glass, or printed designs like the ocean or just flowers and some that are made to look like stained glass. My sis in law has her glass shower doors covered in the most beautiful stained glass design! She said it was super easy to install and reminded her of the fun lil window decals the kids stick on the windows to decorate for every holiday! Good luck :)

I like the film idea everyone is talking about. We have this product from Target : https://www.target.com/p/etched-glass-window-film-silver-roommates/-/A-54171493?ref=tgt_adv_XS000000&AFID=google_pla_df&fndsrc=tgtao&CPNG=PLA_Home%2BImprovement%2BShopping_Brand&adgroup=SC_Home%2BImprovement&LID=700000001170770pgs&network=g&device=c&location=9058203&ds_rl=1246978&ds_rl=1247068&ds_rl=1246978&gclid=EAIaIQobChMIuMrptoat4QIVh8DACh2A7AIaEAQYASABEgJQE_D_BwE&gclsrc=aw.ds

Buy some glass etching cream in the craft department. Just brush it on where you want privacy and wash off in recommended time. Can use adhesive stencils if you wanted a design. Caution...everywhere the etching cream touches WILL be etched