Our five year old Poodle weighs 10 pounds and is reluctant to eat her dry dog food.
I was wondering if anyone has solved the problem by adding or substituting wet dog food or by adding broth of some kind.

I'm not sure of your situation, but here are some of my thoughts. Does your vet believe she is underweight? I personally don't believe in tempting dogs to eat more by adding other foods unless they is a medical reason for doing so. As dogs age and their activity decreases, they often reduce their food intake.
If your dogs appetite has recently decreased and there has been weight loss, I would consider seeing a vet to rule out other issues. My vet once recommended adding a bit of water and warming it in the microwave for 5 seconds for an elderly dog with bad teeth. While I know your dog is still relatively young, I did notice how excited my dog got because the food smelled so rich when doing this. It might be worth a try before adding other things to your dogs diet. Good luck.

Has she ate the dog food all of her life? Maybe it's time for a change! You try eating chicken noodle soup ever day and see how you like it! Sometimes a change is all they need.
Or you could try buying some dog gravy to pour on the kibble.