Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hello,
In Office 365, there are two password policies available, one is set up users passwords never expired ( not recommend) and another is setting up to a period time to expire and notify users before expired. For more details, you can see https://support.office.com/en-ie/article/configure-password-expiration-policy-18d7b2a1-12d1-4e88-9f68-f25c99c54529#ID0EAABAAA=Transcript.
Moreover, the Office 365 password policies are controlled by Global Admin, if you want to change the password policy, you need to contact your global admin to help you check them. For your reference https://docs.microsoft.com/en-us/office365/admin/add-users/set-password-to-never-expire?view=o365-worldwide.
Hope it is helpful for you.