Want to erase all files on my anyehere backup external hard drive

I’m confused on how to wipe My Anywhere backup drive I would like to start over backing up dont have hardly any space left on drive and very new to these drives

From the computer/my computer window you can right click on the external hard drive and select the option to format, you can also do it from the disk management window. If you have a Mac, you can do it from the disk utility app. Check the link below for the steps.