Thanks for the question, the free version says what additional content is in the full version but I didn't think to put it on the description here until just now.
The free version has everything you need to play and have a great time. This includes the Introduction, Playing the Game, Creating a Character, Game Master, and References & Printouts chapters.
The full version also includes over 40 more pages. The Tables & Generators chapter has tables to roll for Friends, Locations, Enemies, Treasures, and Adventure outlines to tie them all together. It also has a series of tables for creating new and interesting magic item ideas. The Advanced Play chapter has sections on Optional Rules, PvP, Writing Drives, Analyzing and Writing Moves and Playbooks, and Playing Solo or in an Open Table. It also includes examples and writing guides for Adventure Starters - initial scenarios to jump into the action fast - and for Legends - mini-playbooks that expand a PC’s capabilities.
I hope that helps.