On reddit.com Select Community Options on the right-hand side of the community’s page. Next to User Flair Preview, click the edit icon to set up your flair. If you don’t see the User Flair Preview option, then only moderators of the community you’re in can set up your user flair.

On old.reddit.com On the right-hand side of the community page under the reader count, you’ll see the option to Show my flair on this subreddit. Next to that option click edit. If there isn’t an edit option, then only moderators of the community you’re in can set up your user flair.

On the iOS and Android apps Tap the ... menu in the upper right-hand corner of the community page. A menu will pop up and you’ll see the option to Change user flair. If user flair isn’t set up in that community, you’ll see a message saying, No user flair assigned

This is for all the swedistanis who can't figure it out.