Welcome to the Forum.
Please don't be offended but we have no way of verifying the accounts and passwords you wish to access belong to you, and thus giving you direct assistance here is not possible.
Having said that, some advice on the assumption these are your email accounts:
- The Windows 10 Mail app is merely a tool to give you access to email accounts on your ISP or within a web-based email account. The password you stick here allows the app to access those email sites using the authentication protocols you were told to set up.
- Thus the passwords used to access these are set on the sites themselves and not within the app itself per se. Hence your best bet is to contact whomever runs the sites your email accounts are set up on and get them to reset your password and email you so you can set them up again with a new password that you can remember.