Brave has password and username autofill. Once you log into a website, it will prompt you to save your credentials. It also can leverage iCloud or other 3rd party password managers (e.g. LastPass, 1Password, Bitwarden, Dashlane, etc…).
We currently do not have a UI to add or delete specific entries, but once you login and hit “remember”, it should auto-fill the next time you visit that website.