They were for a 401(k) plan I was updating RMD choices. I got the PDF form from their site, filled it out in Preview, pasted my signature PNG, and used an app on my phone to fax it(!) to their number.
Got rejected. Had to actually print the damn things and sign them with a pen, scan them again with my phone’s camera, and re-fax them.
Was mildly infuriating.