What does customs clearance involve?

custom clearance is a process of getting clearance from the customs that this good is allowed to import to the country.
it involve the prepration of bill of entry mainly which is preceded by some clerical works for example collection of Delivery order from the shipping company , sending online application to customs.
and later the inspection of the goods by inspectors in ports.
preperation of bill of entry involve the deceleration of the goods by the consignee (in case of import) duty collection by customs etc.

Respected sir, Thanks for query Customs clearance is a process which allow a person or company to bring in or bought out goods from and to boundaries of a country.
It involve submission or filing of documents(Invoice,Packing list,Certificate of origin,B/L / AWB / L/R, any other special certificate if needed) to customs authority,value and physical examination of goods described in submitted documents by concerned officer, then value fixing, calculation of customs duty according to percentage allocated to category of goods, and as final payment of duty and movement to consignees warehouse.

ALL ORIGINALS DOCUMENTS IF INVOICE, PACKING LIST,CERTIFICATE OF ORIGIN , BILL OF LADING,INSURANCE ITS A MOST IMPOTENT DOCUMENTS FOR CUSTOMS CLEARENCE

Custom clearance invoices (KSA) are 

1.Commercial invoice with chamber attestation 

2.Packing list

3.Bill of lading (3) for sea shipment

4.SASO / Certificate of conformity / Phyto sanitary vertificate 

5. Certificate of origin 

6. Beneficiary/ supplier bank payment proof

7. Delivery order

8. Custom declaration copy

9. Lab test certificate