By default in Active Directory, the Default Domain Policy establishes the domain password policy for all users configured and stored in Active Directory. It is looks like below: (Start Menu → Administrative Tools → Group Policy Management and Right-click Default Domain Policy and select Edit. A Group Policy Editor console will open and then navigate to Computer Configuration → Policies → Windows Settings → Security Settings → Account Policies → Password Policy)
We need to make sure that a user password is strong and is changed in a periodically. So you can change all that policy setting with double clicking on it. For example “Maximum password age” :
Change Password expire date and click Apply and then OK.
Same way you can change all password policy settings.
On the Explain Tab you can see description about that policy setting: