If you've forgotten your password entirely, you can reset it from the sign-in page or ask an Admin user to reset it for you.
If you're not necessarily an Admin user, but you've changed your name, or got a shiny new email address - you can update your own user details at any time with a couple of clicks.
To update your details, log in to the web app and click the Settings wheel icon in the top right corner.
To update your name or email address, click the aptly-named 'Name/Email' tab.
Remember to click Save!
To change your password, select the 'Password' tab.
You have to know your current password in order to do this; it's a security measure, in case a malicious actor is trying to change your password and lock you out of your account!
Remember, if you've forgotten your password entirely, you can reset it from the sign-in page or ask an Admin user to reset it for you.