Pat the pork loin dry
Season all sides with salt, pepper, garlic powder, onion powder, and paprika
Optional: sear the pork loin in a hot skillet for 2 to 3 minutes per side
Place sliced onions, garlic, or carrots in the bottom of the slow cooker
Set the pork loin on top of the vegetables
Add 1/2 to 1 cup of broth, water, apple juice, or a sauce of choice
Cover and cook on low for 4 to 6 hours or on high for 2 to 3 hours
Cook until the internal temperature reaches 145°F
Remove the pork loin and let it rest for 10 to 15 minutes
Slice against the grain
Serve with the cooking juices or thicken the juices for gravy