Google "D&D 5e Spellbook"

The only reason this app has such a low rating is because people who download it and see that the spellbook is blank dont bother reading.

To load all the spells, go to google and search for "D&D 5e Spellbook" and the second link should be a Reddit post by the maker of this app. The first reply is a link to the spells available in the 5th edition, so just click the link. Once the page loads, copy the url, go to the app, click on the 3 bars at the top, and paste the url. Congrats, you have a complete spellbook!

8732012 about 5E Spell Book, v1.9