So i am currently making a Blood Hunter and I was wondering. Can you make a vampire that’s also another class. So for example if a Ranger or Fighter or something was also a Vampire. Is that possible? If so how would it work? Would you just combine the two classes abilities or what? 

Vampirism is more of a race template thing. You either become a Vampire or Vampire Spawn or you keep your race but add or change things to reflect the vampirism. Or you can create a homebrew half-race like I did (see link in my signature for my homebrew races, the half-vampire is "Dhamphir").

Nothing stops you creating a subclass based on vampirism or blood. Sorcerer seems to be a good choice, I made a Blood Mage subclass which is currently awaiting moderation. There are existing official "blood" based subclasses and some from campaigns. Like, for instance, there's a blood domain cleric in Matthew Mercer's Tal'Dorei Campaign guide.

I suppose it is possible to create a vampire class but this would be your homebrew.

Awesome sounds cool. I’ll work on that. Thanks you for the help!