I wanna learn video editing but im not sure which program is best. Which program do studios or professional youtubers use.
It depends on what you want to do with your YouTube account. What is your operating system? How good is your PC? Which camera do use?
For example, for vlogs, a simple Magix/Premiere Pro Elements/Final Cut solution is totally sufficient. If you want to do more complex work, like color correction/effects/animations/handle RAW files/etc., I would recommend Premiere Pro (PP) as it has a lot of features and, in combination with the other Adobe products, handles most aspects of post-production. Premiere Pro is also a little bit harder to learn because it has many advanced capabilities.
I started with Sony Vegas, but as soon as I used PhotoShop and After Effects the first time, I immediately switched to PP as it used the same environment as well as similar looks, workflows, and shortcuts. And since I am used to it, I don't want to switch to any other software.
As far as I know, in the YouTube scene (especially the German one), most of the lifestyle vloggers use Final Cut and most of the more "technical" ones (gamer, unboxer, etc.) use Premiere Pro. If they produce more complex work like short movies or a high-quality series, they all use Adobe products. Some of the really professional big channels combine those products with DaVinci Resolve and 3D Software like Cinema 4D.
So to sum up, I would recommend for you (if you can afford it) to start with Premiere Pro. There are a lot of good tutorials for every aspect of the software. But do not forget that software is not everything! The better your footage and content is, the better is the overall quality of your videos. So try to learn aspects of camera tricks and script writing as well!