In case you should apply to the NSSF or not, you may yearly pass by the NSSF Office or send them an email on time.

If you are already registered, you should bring the official documents (NSSF, COOP, Army, under the name of your parents, the company you work in, etc.)

If you are not registered, you only need your national ID and a document proofing that you are not covered anymore if you were previously covered.