I don’t believe there is anything for that beyond “Logins & Passwords”, I know that’s not what you want with what you said, but I can’t see any places for that within Brave itself…
OUTSIDE of Brave though, there are options with iOS that you can use, such as when you get to a form, it can fill in your own information if it’s setup in your contacts…
The support article below says it’s for Safari (since obviously that’s Apple’s default) but the information shared in the first article below also (at least, mostly) applies in Brave:
You can also use the iOS feature: “Text Replacement” to further customize things, see second article below: