You can change your Console password whenever you need to, for example if you think someone else may have seen it.
Open password settings
Click your account name at the bottom of the left sidebar, choose Settings, then open the Password tab.
Change your password
Enter your current password.
Enter a new password, then enter it again to confirm.
Click Save.
For an extra layer of security, also turn on two-factor authentication (see Securing your account with two-factor authentication).
What this does and does not change
Changing your Console password only changes how you log in to the Console. It does not change the SSH/SFTP password for any of your sites. Each site has its own SSH/SFTP password, which you can view and rotate under Hosting, then SSH / SFTP (see Connecting over SSH and SFTP).