How do I change the admin name on my MacBook air

First make sure you have a good working backup of your Mac in case you make a mistake.

Here is an Apple article with instructions:

https://support.apple.com/en-us/HT201548

Make sure to follow these instructions exactly. If you skip a step or mistype the new name at any one of the steps, then you will lose access to your data and will need to restore from a backup.

Make sure you have a good working backup of your Mac in case you make a mistake. (Yes this step is extremely important if you value your data)