Nameplate with more than 12 characters?

Hey there, a bit new to the Xbox app so this may be more obvious than I'm perceiving. If so however I have struggled to find any information on it. On occaison I'll run across players with names exceeding the usual 12 character limit, usually players with in-character pirate names reaching high as 18-20 characters. How would I go about extending my name? Or is it perhaps an old character limit that has since been restricted to a smaller number? Thanks in advance.