We have a moen faucet in the shower it is only a shower no other faucet there. We have hot water in the sink, but not in the shower. The water flow is fine in either direction. What should we do, we just moved in and desperately need to shower lol.

Hi ijacobs and welcome to The Plumbing Page at ANHD.com. Sounds like you have a blockage in the inlet ports of the cartridge, How often do you flush out your water heater?
Shut the water off and remove the cartridge and check and clean the hot water inlet ports. Now turn the water back on for a few seconds to flush out the supplies. Reassemable and test. Better now? Good luck, Tom