Sure you can. I am a regular online shopping customer. And you don’t need to worry if there is something wrong with the glasses cause the return/exchange policy is quite efficient.
I don’t recommend it if you have never bought progressive lens online. Glasses are customized products and it’s better to buy them at a local store. Just in case you might get the wrong prescription.
I would also prefer to buy them at a physical store, but we cannot deny that the price is so much cheaper from online. Either way is fine as long as it it within your budge.