A supporting document in the EBA DMS is accompanying document of a main document where certain additional information about the document is recorded.
It can be set to automatically transfer data from main document so that you don’t need to actually search for certain information on the document. For example you can set field on supporting document to show you contract expiration date and you don’t need to scroll whole document to find it.
The supporting document is visible in the document window in the tab supporting document in the document details pane, the data of the supporting document is a search criterion and is also available as columns for display in the document list in the document list view.

You can format the supporting document in any way you like, define which data it should contain, which of these data are mandatory, define drop-down selection lists for easier work with fewer errors.
Lists of field values can draw data from several different types of databases. You can link the data on the supporting document to the data on the document, which automatically updates the data on the supporting document when the data on the document is identified.
In Administration > Document Settings, supporting document section, you can create and edit supporting documents for individual document types or for all document types (globally), for individual document directions or globally for a selected document type

If there are several supporting documents, they are displayed together on the document, one below the other.
In the case of multiple companies, you can create a supporting document for each company separately or a common one that applies to all companies.
Normally, a supporting document is created for a specific document type, but if you create a global supporting document, it is valid for all document types.