GRN is nothing but Goods Received Note.

At the time of delivery from the supplier to the person who 
orders the goods, the person will check the quantity and in 
terms of quality.  

He will ensure the ordered quantities are received without 
any damage.

The store keeper will put the GRN only those goods which 
were received at his counter.

Then the stores ledger will be Debited with GRN with 
concerned material code and credit when it is given for 
consumption

Hi,
Goods receipt note (GRN) packing for a goods receipt
materials and items (within a goods receipt) to be packed
for subsequent shipment to the remote location. Goods
movements are created in Materials Management and, where
necessary, reflected from a Profit Center Accounting point
of view via a special account determination.
goods receipt has the following functions:
    * Quantities on the delivery note can be entered

The quantities can be entered exactly as they are on the
delivery documents, irrespective of whether they deviate
from the order quantities.
Goods Receipt is a Quality Manager role Monitoring the stock
in quality inspection and processing inspection lots for
goods receipts.
Monitoring inspections.
Making usage decisions and triggering corrective tasks.
Monitoring appraisal costs, nonconformity costs and
prevention costs.
Analyzing quality results.

    * Order items can be assigned and arranged

The purchase order items are arranged to correspond with how
they are listed on the vendor’s delivery note, making
further processing easier.