Q. How can I set Azure AD passwords to never expire?
A. Using the Office 365 administration portal it is possible to set passwords to never expire, this is done through Service Settings - Passwords area as shown below by checking the Passwords never expire option.
This can also be configured using PowerShell but configured on each user. In this example I fetch all users then assign the password to not expire:
Get-MsolUser | Set-MsolUser -PasswordNeverExpires $true