You don’t log in with a username and password on Jungle. Every time you log in to your wallet, you are connected to your Jungle account - the two are linked together. Using a different wallet? You’re using a different account.
If you can’t access your wallet (and therefore your account) and need to reset the password, we can’t do that as we’re not your wallet provider - you would need to contact them directly for support. Many wallet providers have a guide or FAQ section that tackles the relevant steps for a password reset, like this one for MetaMask.
You can adjust other details via Jungle - like the email address associated with your account, for example.