You can delete the category by following the below-mentioned steps:
From the left side menu click on "Inventory" -> "Categories"
You will land on the Category Manager Page.
Under Action section, move the cursor and click on the little bin shown next to the category you want to delete. The selected category will be deleted right away then.
Delete Multiple Categories Option
If you want to delete more than 1 category in one go, you will require to tick mark the check box on the left side of the category name or category image.
Once you select multiple categories, go to the “Action” option on the top bar →
Click on “Delete categories”.