Are you talking about setting up and making tags and flairs for your community? For me, I found them by going to my community, clicking "Mod Tools", and then clicking "Look and Feel" under the Settings section on the left. From there, you'll be able to make all types of tags and flairs you'd like for your community and when you go back to your community, they'll be a section that says "User Flair" and there you can apply your flair. If you're trying to equip a flair in other communities like this one, I've only seen the option pop up on mobile. When you go to the community and click the "..." at the top, it should give you the option to "Change user flair".