Your password is needed to log into your account. It is best to use something you remember, but that is not one you use for other games or websites.
Changing Your Password
To start the process of changing your password you will need to navigate to the My Account tab by going to the top right hand corner of the website and hovering over your username and avatar.
Once you are on the account page you will need to then click the Manage Twitch Button that will take you to a Twitch settings page for your Twitch account.
While on the Twitch settings page you will need to navigate to the tab that says Security & Privacy and click it to be taken to the Security & Privacy section.
While on the Security & Privacy settings page you will need to navigate to the section that says "Change Password". It is the very first setting on the page. Once you locate that setting you can go ahead and click the link that says "Change password".
Once you click that link you will be taken to a page that will ask you to enter your old password and then to enter your new password. You do have to enter your new password twice to verify that it is the correct password that you would like to use.