You must enter a document header text for document type &

What causes this issue?

You have not entered a <LS>document header text</>. Customizing is
configured in such a way that a document header text must be entered
for document type &V1&.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Check the document type. If it is correct, you must enter a
<LS>document header text</>.

Error message extract from SAP system. Copyright SAP SE.