Hello wsnowina, If you want to change a Firefox account password, click on follow the steps below.

1. Click on your avatar on the toolbar. Then, click on account settings.

2. Click manage account, and scroll down to Password.

3. Click Change... and do your thing.

Tell me if I helped and Stay Safe!

Hello   wsnowina,

In addition to the above,   and as you don't mention for what account you want to change your password;   would you please take a look at these articles :

https://support.mozilla.org/en-US/kb/change-your-firefox-accounts-password

https://support.mozilla.org/en-US/kb/reset-your-master-password-if-you-forgot-it

https://support.mozilla.org/en-US/kb/password-manager-remember-delete-edit-logins