Instagram added a new feature to its mobile app called Nametag. With Nametag, you can create and customize your own nametag, that others can then scan to follow you.
The Nametag option is under the menu on the top right of the screen on your Profile. From here you can customize your name tag.
To scan someone else’s tag, just go to the same menu and you will see the option to scan a name tag at the bottom. Just point the phone’s camera at a nametag and their account will show up on your phone.
Admittedly, this is only slightly easier than manually typing someone’s username on your phone to follow them but if you don’t want to do that or if someone has a particularly long and complicated handle, you could just now use the Nametag feature to add them.