The Basis tab contains a lists of documents used as the basis for this tax invoice received. The Basis tab is available if the transaction type is Receipt and the Summary check box is selected. In this case, you can include multiple invoices received.
The Tax Invoice Received (Create) form. The Basis tab
To add a document to the list, click Add, select the document type, and in the Basis column, select a particular document of the selected type. Repeat for all the documents to be added to the tax invoice received.