I changed my job in Nanjing. My previous and present units were from Nanjing. What are the procedures for social security transfer?

If both the original unit and the new unit are from Nanjing, there is no need to go through the transfer procedures. If it's a new unit in the field, transfer it.

1. At present, only endowment insurance can be transferred nationwide, and some cities with medical insurance can transfer it. With your ID card, instead of yourself, you can issue a payment voucher for old-age insurance in the social security bureau of the place of payment and hand it over to the social security bureau of the newly insured place. I'll inform you after the specific transfer procedures are completed by the Social Security Bureau!

2. Maternity insurance and industrial injury insurance among the five social insurances cannot be transferred!

3. Provident funds can be transferred, but cash can also be withdrawn, which is relatively simple and cost-effective. Social Security Hotline 12333, Provident Fund 96 166.

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.