To provide secure transmission of customers articles. A record is kept at all stages the article  passes through. Also the registered articles are transmitted , under special precautions. 

Articles which can be registered 

Registration is compulsory  for the following  

Any parcel exceeding 4 kilograms in weight.
Any insured article
Any parcel addressed to a place for which a customs declaration is required.
Any article containing  the following 
stamps labels,  cheque, hundi, bank note, bank post bill, bill-of-exchange, 
Any article bearing the word “registered”  on the cover.
Any registered article which is re-posted after having been delivered.
Any value-payable article

How to register?

1) An article intended for registration must be presented at the window of the post office.

A receipt will be given to the person who presents an article for registration at the post office window during the hours prescribed for posting registered article

2) No such article shall also be accepted for registration –

(a)  Where it contains words to the effect that it has been, or is intended to be insured for any specific sum, or that is may contain valuable contents unless it is also to be insured, or

 (b) where such words are scored out.