You may change your password or email address or both.

Explain

When you come back to this website, will the computer here recognize you? So you don't have to start over?

The computer here recognizes you by a "cookie" it put in your computer. This is very normal. If this didn't happen you wouldn't have gotten anywhere on this website. As long as you don't intentionally erase your cookie, you will have no problems connecting back to everything you have done here. (And if you just want to start over new every time, then you still have no problem.)

But if you want to logout, or if you want the computer here to recognize you when you are using a different computer, you need a password. (Logging out erases the cookie in your computer so the website can't recognize you.)

Choose a password that no one else will select.

If you forget your password and would like to be reminded what it is, then you have to have an email address on file. (Your email address otherwise is never used.)