MetaMask uses passwords in a way that you may not be used to. This mainly has to do with the fact that MetaMask is a self-custodial wallet (also called non-custodial, though we're phasing out this term); it's not a conventional cloud-based app where we keep track of your username and password.
You keep track of your Secret Recovery Phrase, and each time you restore your wallet using your Secret Recovery Phrase, you set the password for that specific instance of MetaMask.
This means that if you use different passwords for each instance (Mobile, Extension, Extension on different computers or browser profiles), you need to remember which password you used for each instance.
User guide: Secret Recovery Phrase, password, and private keys
How to use multiple MetaMask wallets