First you should go to endocrinologist (You can skip this part but you might get lucky), to see if you hormones are at a natural level, if they aren't then the doctor will be to source them for you (For a price of course).
If the endocrinologist is a cuck and is bluepilled (Very likely) and tells you your hormones levels are "natural" and that you don't need them you will have to source them a different way, from the internet of course. It is not really that hard, just type "how to buy hgh" into goygle and there will be many guides on ways to do it. Once you order it and it arrives you should do a test to make sure it is the real thing. Again you can find out how to do this from google but if you get pharma grade shit you know it's real anyway.
If you don't want to try or can't get hgh you could always try something like mk 677. Pure hgh is the best way to do it though.
As you get older you will also want to keep you plates open so lowering your estrogen (Estrogen is what cause male growth plates to fuse) is also important. You can use natural estrogen inhibitors for this or use drugs,
There are many guides on heightmaxxing for openplatecels