How do I turn my hard cover books into ones I can read like on my phone, tablet, or laptop?

The bar code on your book is either the ISBN (International Standard Book Number) or a barcode used by the publisher or seller (to track inventory) It won't display the text of the book when wanded.

Most books also have e-book editions. Your local library has thousands of titles available.

No

There isn't an app to give you free digital copies of books you own, because you don't legally own digital copies of those books.

That would be copyright infringement (i.e., illegal) unless the book is old enough to be out of copyright (in which case, you just download it from Project Gutenberg).

Amazon has a programme called Matchbook, whereby if you own the paperback or hardback of a book, you can get the ebook cheaper or free, but (1) you have to have bought the paper book from Amazon and (2) the publisher or author has to agree to let Amazon give you the ebook or sell it cheaper.

Many libraries now lend ebooks.

You will have to buy them separately if you want to own both formats. That said, many libraries have digital copies of books that you could borrow. I borrow ebooks all the time from my library.

You will have to buy a digital copy of the book through Kindle or other e-reader. Scanning the books as Athena suggested is a violation of copyright. Just because you buy a hard copy doesn't mean you're entitled to a digital copy.

You just scan them using your printer/scanner and save them to a PDF format. That is a universal format all your devices should be able to read.

If your phone does not recognize PDF, and it should, then save it as a RTF file.

Find a technology expert.