Resetting a user's password is a permission reserved only for Organisation Admin and Project Admin users. If you've forgotten your password and can't access your account, you'll need to contact your Project's Admin or Organisation's Admin to have it reset.
If you know your current password and want to change it, check out this article here.
Step 1: From within the Admin area, click 'Users'.
Step 2: From the Three Dots Menu ( ) against the user's name you're looking to reset, click 'Reset Password' and follow the steps.
Step 3: Once you've reset a user's password, you'll need to let them know their new password. Be sure to send them an email with the new login details!