Direct type specification has been enabled

What causes this issue?

You have enabled direct entry for the data type, length and short
description of a field.
You can mix this kind of field with fields whose attributes are set by
specifying a data element and domain.

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?

Ensure that fields without a data element have only a restricted
function. If you use a field on a screen, it should always be linked to
a data element.

Error message extract from SAP system. Copyright SAP SE.