There are Rabbis everywhere, how to identify who is a real Rabbi if the Rabbi is not included in a recognized organization, such as Israeli Supreme Court or RCA etc.? Does a Rabbi need Yeshiva study with a certificate? Or anything else?
Yes, to become a Rabbi you need to go to Yeshiva and study and get a certificate of ordination from the Yeshiva (or University).
Besides the RCA, there are many other orthodox communities that have their own standards, but they are mostly similar. Each community/Yeshiva have their process by which a potential rabbi studies the applicable daily laws a rabbi would need to know, and then gets ordination.
I dont know if the title 'Rabbi' is governed by any legal ramifications of law. so that's why it's important to look into each rabbi's ordination and certificate.
If you are not familiar with the process you should definitely find someone who understands and knows more the processes and ask their opinion.
See comment from user rosends with Wikipedia links.