You may be used to logging in to an account with a username and password, but your account is a little different on OpenSea.
Your account on OpenSea is tied to your wallet, so you don't log into your OpenSea account with a traditional username/email and password. Instead, each wallet you've connected to OpenSea is its own account. It's important to note that OpenSea isn't a wallet provider, so we never take possession of your assets or take custody of your NFTs. That also means we can't provide password resets.
In order to reset your password for your wallet, you'll need to contact your wallet provider directly or search for the relevant help guide. As an example, here's MetaMask's help article about resetting your password.
You can, however, edit the email address for your account by going to your profile settings.
Learn more about editing your account in our help guide, How do I create an OpenSea account?