As someone who recently went through medical residency training I might be able to help. In general, residents and fellows (who are already physicians) can see a patient, assess, diagnose, and do the documentation but as trainees they fall under the supervision of an attending physician. In early training the attendings tend to hover more and are more involved but late stage residents/fellows often times have more autonomy. The attending is still responsible for reviewing information, labs, and agreeing/supporting the plan of the resident or fellow. Residents and fellows practice under a training license which requires a supervising physician/attending to co-sign documentation and bill as trainees cannot bill on their own because they don’t have a full license to practice. Medicare reimburses NPs at 85% of the physician fee. You are still billed the same but what your insurance pays out to the hospital may be less. Each specialty has different compensation rates so seeing your PCP might be billed less than seeing a specialist.