To allow your agents to sign in via username and password, you must first check the box next to this option in Settings > Security > Console Sign-in. Once that is complete, you can follow the steps below to change the expiration time frame of passwords.
Allow Username/Password Login
1. Click Settings > Security > Console Sign-in
2. Select Username and Password
3. Save Changes
Update Password Expiration Policy
1. Click on Settings
2. Click on Access Management
3. Select "Set Password Expiration Policy"
4. Type the number of days for password expiration
5. Click on Save Changes