Hello @lcaverly
In iphone devices, all login details saved in iCloud Keychain. Follow mentioned-below steps to remove the saved passwords...
- Open the Settings app on the iPhone.
- Scroll down to the Passwords menu.
- Authenticate yourself using the password or Face ID.
- Use the search bar to find the item you are looking for at the top.
- Tap on the website name and select Delete Password from the following menu.
Besides, You can also long-press on the website name, and it will open the pop-up menu to offer the delete option.