Keychain Password User Name

Hi rgtob, yes, you can!

It looks like you're using an iPad Air on iPadOS 15. To change the details for a password or user name you have saved with Keychain, follow these steps:

1. Open Settings
2. Scroll to Passwords
3. Search for, or locate the account you're trying to update
4. Tap on the correct account
5. Tap edit on the top right
6. You can now edit the user name or password for the account, or perform other tasks like adding a note.

The process will be similar on an updated iPhone. If you require assistance with updating your Keychain accounts on a Mac, let me know.

Yes you can. Go to:

Settings -> Passwords

Find the site for the username you want to change and tap on it. Press Edit in the upper right corner and change the username.