Look at the lokal Immigration Office’s website, for information, there you will get the actual information, from that office, since there are different how the Immigration Offices handle the situation.
Some places you can get it almost from the beginning of the stay in Thailand, other places not until after 3 month, which is the “by the book” way.
It also depends of what you need the certificate for.
Write the answer here in the group, where the question has been asked, that’s the way we keep the group interesting to read, and there would be several that could benefit from the answer when posted in the group.
There should be no money involved, for answers to questions put in this group