This option allows you to quickly add a group of items rather than adding them individually. This means the group of items is expressed as a single item on your line item grid when you select this item from the drop down list. Keep in mind this list can't be altered within the line item grid of, for example, an invoice, so it's a good idea to create group items for recurring orders you know won't change.
To add this as an item, you will need to add a new item within the Items app, and choose Sales Tax.
If you do not see the Items app, you will need to get access permission for this app from your administrator. The Items app is found in the Accounting Lists Pack.
Because you’re referring to a group of items rather than an individual item, there is a List at the bottom of the screen that details which items are included in the group. So the individual items are displayed here, and on your main items list, the Group item (containing these individual items) will be displayed as a single record.