The phrase "digital format" refers to storing and displaying information using computers or electronic devices instead of using physical objects like paper or vinyl records. Full definition
It is a gadget that translates books in digital format for our eyes to read. (goodereader.com)
They also come in a variety of digital formats for whatever digital reading platform you prefer. (techtimes.com)
Now, more than ever before, publishers are demonstrating that they are committed to the development of digital formats in their publishing programs. (goodereader.com)