If your computer is on a domain, only your network administrator can change password policy settings.
You can help protect your computer by customizing your password policy settings, including requiring users to change their password regularly, specifying a minimum length for passwords, and requiring passwords to meet certain complexity requirements.
Open Local Security Policy by clicking the Start button , typing secpol.msc into the search box, and then clicking secpol. If you’re prompted for an administrator password or confirmation, type the password or provide confirmation.
In the left pane, double-click Account Policies, and then click Password Policy.
Double-click the item in the Policy list that you want to change, change the setting, and then click OK.
This table lists the password policy settings that are available, explains how each setting works, and provides a recommendation for each setting.