Is there an MM workflow available to have a goods receipt or service entry approved prior to it being posted.
There is no functionality as such for the requirement, but for goods receipt you can activate Quality setup in the material master - in quality view as inspection setup. For PO with goods receipt inspection setup is 01,04, and 08. Also to be more specific you can setup result recording and Usage Decision based on which you can clear the goods to required location also for service entry you can have release strategy for the same activated.
QI01 - Qualtiy info record
QA32 - inspections setup
QE51n - Result recording
QA16 - UD