To change email password please login to https://outlook.office.com/owa/ and follows below steps.
- Click on your name, located in the upper right corner.
- Click my account.
- Click On Security & privacy then click on change password and enter here old and new password accordingly and click on Submit.
- Close any open webmail windows and click the OK button. You will then have to log back into webmail, and same password need to update on outlook as well.
Or you can use below url for same as well.
https://portal.office.com/account/#security