What is dual certification for going abroad? Is it complicated? How to deal with it

Because domestic documents are used overseas, dual authentication, that is, consular authentication, is required in some countries, and the whole process is carried out in China. The authentication process is as follows:

Submit it to the notary office first.

Secondly, submit the notarized documents to the foreign affairs office for certification.

Finally, it was sent to the country's embassy in China for certification