Here’s how it works on the Instagram app on Android and iOS devices.
Make Your Instagram Account Private
Making your profile private is quite simple.
TapMenu(three horizontal lines) in the upper-right corner of the screen.

UnderAccount Privacy, toggle onPrivate Account.
The option is in the photo menu.
You’ll need to turn the privacy setting off manually to let everyone see your feed.
FAQ
Only the users who follow you will be able to see it.
It will not be visible to anyone else who does not follow you already.
To stop someone from following you, block the account.
(If the account holder is behaving inappropriately, considerreporting the account.)