How do you sell your self-published work? Can you sell it only if it's digital? Or can I sell physical copies too? Thanks.
Most self-publishers rely pretty heavily on Amazon - check out https://kdp.amazon.com/. You can get your book into other online bookstores through Smashwords - https://www.smashwords.com/. Print books don't sell as well b/c most bookstores won't stock them, but an easy way to make them available is Createspace, https://www.createspace.com. There's also Lightning Source and other companies that do the same thing, but I've never used them so can't comment on anything beyond their existence.
It's worth checking with your local book store on print books. The local B&N here will put them on the shelves, apparently, as will a small local bookstore. But of course you're not getting chain-wide B&N distribution, just a few copies in the local store.