Open your Microsoft 365 Profile Card. You can do this by opening any email sent to you and clicking on your name.
Step
On the profile card, click the camera icon next to your current profile picture.
Step
A window will pop up allowing you to edit or upload a photo. Click Upload a new photo, and browse your local hard drive to upload a profile picture.
Step
Once you've selected a new photo, click - or + to change the zoom, and drag the photo to adjust what shows in the window as needed. Click Apply to update your new account picture.