Thanks for clarifying,  @Anonymous !

This was related to the following answering below by  @KhimG :

"The markup box will only show on your invoices if the item or product you’re using has a markup on it. To add a markup on an item, follow the steps below:
1. Go to List on the top menu bar.
2. Select the Item List.
3. Double-click on the item you want to markup.
4. Click Edit Markup tab on the right pane.
5. On the Type of Markup, select Use default (“Percent over Cost”).
6. Under the Markup Percent, enter 20%.
7. Click OK to save and close.
8. Click OK again to exit from the screen. "

If this was copy/paste answer, I'd suggest also providing the URL link to that QuickBooks Help article. That helps, I think!