Step 1: Step 1: Login into portal.office365.com
Sign in with your Login ID and Password.
Step 2: When entering account click on Admin as shown into the picture.
Step 3: In the Office 365 admin center, choose the Active users option.
Step 4: Click on the Three Dots in front of user as shown in the picture, and then click on the Delete User Option.
Step 5: Now a new window will appear, here some options are available regarding the user deletion, (from here we can assign the existing license to a new user if we want) click on the Delete option.
After clicking on the delete option we can see that our user is successfully deleted.