Privacy is very hard for anyone backpacking, you have only the tent and the woods, maybe a large rock you can get behind. With hiking you have to keep clean, keeping organized hygiene wise and pack wise. Many hikers have no care about privacy or don’t make it a huge deal, but the ones that do have many things to learn.
First it’s hard to imagine yourself having privacy on the trail, but truly your as private as you can get in the woods. Their is usually no one there and if they are they most likely will be polite and let you be.
Secondly, tent or tarp privacy is hard to obtain many hikers that use tarps (me included) your privacy is less with that, so keeping it private is much harder. Focusing on where you setup your tarp or tent is key for as much privacy as possible.
Lastly, I would just say most hikers or people in general will be very okay with you saying, hey I’m gonna go in private and do some personal stuff I’ll see you later. Don’t get nervous about wanting privacy for any reason. Let’s be considerate to everyone and give the privacy needed.