Great article: link to MS
Change my password in Office 365 for business
Applies To: Office for business Office 365 Admin Office 365 Small Business Admin
- Go to office.com.
- Sign in with your work or school account.
- Go to Settings > Password.
- Follow the instructions on the Change Password page.
Tip: Some users can’t change their password in Office 365 because their organization creates and maintains their accounts.