My Dog Is Peeing Himself When He Sleeps, Can You Help?

Dogs should not urinate while sleeping. The bladder muscles should maintain tension to keep urine in the bladder. Incontinence can be due to irritation of the urethra, irritation of the bladder, bladder stones, infection, muscular or neurological abnormalities.
As dogs age incontinence can become a problem due to cognitive issues, arthritis issues (pain when posturing to urinate or get outside to urinate), and the above medical problems.
Have your dog examined by a veterinarian. The first step will be to run a urinalysis. Medications will be prescribed to treat the primary problem and also are available to help tighten sphincter tone.

Not sure how old the puppy is, but I think she possibly hasn't learned bladder control. Make sure you take her out before bed, and you reward her with a treat when she does what you wanted her to do. I think this should pass soon, but if not you may want to have a vet test her for urinary problems

Sounds pretty normal.... They might have training for that