How can I delete One or Multiple List Columns?
You should have a permission to can delete List columns,
List Settings > Below Columns > click on your column that you need to delete > at the bottom of page > click delete.
Note : the title and built-in columns can't be deleted it can only be renamed or hide.
You should have a permission to can delete Items within a list. To delete items
- Open your list.
- Select the items that you need.
- from the above ribbon > at List tab > select delete.
If you didn't have permission to do that it will be grayed out / disabled.