Order category of purchase order & not possible here

What causes this issue?

You have entered a purchasing document whose order category does not
allow a goods movement.
Goods movements are defined for the following order categories only:
<GL:purchase_order>purchase orders</>
<GL:scheduling_agreement>delivery schedules</>
<GL:release_order>contract release orders</>.

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?

INCLUDE NA_EINGABE_PRUEFEN
INCLUDE NA_BESTELLUNG_SUCHEN

Error message extract from SAP system. Copyright SAP SE.