Step 1: Click edit your page from your creator page:
Step 2: Click about from the top menu and scroll down to the Patreon URL section:
Step 3: You will see a Patreon URL text box where you can enter your preferred URL name and we'll let you know if it's not available with a red line.
Step 4: Don't forget to scroll back up and select save changes!
If you see a red line when attempting to create a custom URL, this means that the URL has already been claimed.
Patreon custom URLs are claimed on a first come, first served basis. Even if the Patreon page seems inactive, Patreon is unable to free up that URL.