To summarise those two very good answers
There are 92 that exist naturally on Earth, Hydrogen to Uranium
In addition to those there are another 25 that we have made artificially making 117
Most of these only in tiny, tiny amounts before they decay to nothing.
Element number 117 has not been created yet, it might not be even be possible to do so so it's penciled in as it were.
So the answer is 92 if you want natural stable ones, or 118 for the ones that are actually written in or 117 for the ones that have ever been seen.
3 answers in one - bargain!