In the Local Security Policy (Search from the Start Menu). Navigate as following,
Security Settings > Account Policies > Password Policy
At the right panel, look and double click for Password must meet complexity requirements. Click Enabled.
So, once you activated this option, the following minimum requirements must be meet:
• Not contain the user’s account name or parts of the user’s full name that exceed two consecutive characters
• Be at least six characters in length
• Contain characters from three of the following four categories:
• English uppercase characters (A through Z)
• English lowercase characters (a through z)
• Base 10 digits (0 through 9)
• Non-alphabetic characters (for example, !, $, #, %)
• Complexity requirements are enforced when passwords are changed or created.
