Morning Sandra - did you get anywhere with this?
For the Proof of Licensure - I took this to mean, proof of your licensure with the Board of Pharmacy in your Home Country.. So here in the UK it would be proof of my registration as a Pharmacist with the UK General Pharmaceutical Council (GPhC).
Request from the board to send your license to NABP as per their instructions. You may have to pay a small fee for this