By hovering over the Settings gear icon in the upper right-hand corner and selecting Password Settings, you will be presented a window to define your own password policies for your organization.
From this window, you can manage Password Expiration Settings and Password Strength Settings.
Password Expiration Settings:
1. Optionally select Enforce Password Expiration. This will allow you to;
2. Set the time (in days) that a user's password will expire by entering a number of days in the Expiration (days) field.
Password Strength Settings:
1. Optionally select Enforce Password Strength, which will allow you to;
2. Set a numeric value for Minimum Password Length
3. Set a numeric value for Maximum Password Length
4. Define what values must be included in the password using a regular expression
By clicking the RESTORE DEFAULT STRENGTH EXPRESSION button you can restore all Password Settings to their default values.
For information on how to force a user to change their password on the next login click here.