Enhance password history module documentation

Expanded the description of the password history function to clarify its purpose and functionality.

docs/en/modules/identity/password-history.md

@@ -4,9 +4,9 @@
 
 > You must have an ABP Team or a higher license to use this module & its features.
 
-The Identity PRO module has a built-in password history function.
+The Identity PRO module has a built-in password history function that allows you to enforce password reuse policies for users within your application. It keeps track of users’ previously used passwords and checks this history whenever a user attempts to change their password.  This prevents users from setting a password that they have already used in the past, ensuring that each new password is unique and not a repetition of an older one. 
 
-## Password history settings
+## Password History Settings
 
 You need to enable the password history and configure related settings: