Is it possible to install an unformatted M.2 SSD and install OSX?
Update: I have an M.2 adapter.
I do not have an M.2 enclosure, that would be necessary to ghost the current drive over to the larger drive. If possible, what are the steps?
Unfortunately, it is not possible to install an M.2 SSD into a MacBook Air (or Pro), because Apple SSDs aren't M.2, and (please correct me if I'm wrong) there are no Apple SSD to M.2 adapters, partially because (this is what I've been told) an M.2 SSD has to be directly mounted to the motherboard. Also, it's quite possible that M.2 SSDs are different dimensions than an Apple SSD, and might not fit in the (computer's) case.
You can however buy an Apple SSD from OWC, which should work perfectly with your MacBook Air.