RTFM. Go into settings, there will be a subsection for recording resolution somewhere, which will tell you what the default setting is, and a range of settings to choose from. For most people, the highest resolution .jpg would be perfectly adequate; RAW is fine if you’re planning on doing a lot of tweaking in Photoshop, adjusting white balance, etc.
A 12Mp camera, with a 64Gb card ought to be getting a couple of thousand .jpg photos, at least; I buy a bunch of cheap 8Gb Transend cards and fill those up, then put in a new one, and there must be several hundred on each card.
Just a thought, what make is the card, and where did you get it? There are a lot of bogus high-capacity cards being sold online, it’s possible that’s what you’ve got.