To change the username on your Zoom account, simply click on the icon of the initial in the top right-hand corner of the screen. Select Settings, go down to the Profile section, and click on where it says Edit My Profile. Once you're there, you will be taken to a web browser where you can then click on the small blue Edit button on the right side of the page. In the sections where it says First Name and Last Name, type in your preferred username.
Image Source: POPSUGAR / Lauren Harano