Force Password in cPanel Servers are for security purpose for an certain number of days the cPanel password will ask you to change the password its not like your cPanel/WHM has been compromised.Its an security of an Server or your cPanel account to change the password for Certain number of days
If you forgotten your Current password You can change it from your WHM(If you are an Reseller).
If you are an Shared Hosting client you can change your password from clientarea > my services > View details > Change password
Using the changed password you need to change again once it ask you to change the password again