Ultrasound at 6w3days, what to expect?

Divsu • PCOS, annovulation! Two failed IUIs, IVF - 1st FET- miscarried @8 weeks. 2nd FET failed, 3rd FET chemical, 4th - BFP!!
I'm 6 weeks 3 days pregnant with my first child and scheduled for an ultrasound tomorrow. I got my pregnant through <a href="https://glowing.com/glow-fertility-program">IVF</a> - frozen transfer. 
Someone who has had an early ultrasound at 6 weeks before - what should I expect?  What are they generally looking for?  Can you see the heartbeat this early? Is it going to be vaginal ultrasound? Any information would be greatly appreciated!