This video demonstrated what to do if your Macbook pro/air is not recognizing the boot drive or hard drive. In my case, I had to replace my Late 2013 Retina Macbook pro which I did with a Crucial P2 NMVE M.2 Drive. Link:
I also Utilized M.2 NVME SSD Convert Adapter, 12+16pin M.2 NGFF M-Key SSD Convert Card
Link:
Note: Make sure your model uses the same 12+16 pin as it may be one of the other two pin configurations. Type your own model then SSD adapter into Google or Amazon to find your correct adapter if this isn’t the same as yours.