Eurail is always your ticket (which you show on the Rail Planner app as a QR-code).
Sometimes you need to add reservations on top of the pass (mainly fast/high-speed trains in France, Spain, Italy).
Spain is the worst country as some reservations aren't available online but you can still make it work. France works but you need to book in advance as trains sell out. Italy is easy : frequent trains, reservations always available on the day.
Most trains have optional/no reservations. Depending on route and day (for example Saturday mornings are busy) it might be a good idea to make one.
Have a look at these 2 links :
https://www.seat61.com/how-to-use-a-eurail-pass.htm
https://www.seat61.com/interrail-and-eurail-reservations.htm
About your specific journey :
- Zurich - Innsbruck : 3€ optional but recommended (short train, popular route)
- Innsbruck - Verona/Bologna : 10€ passholder supplement + 3€ optional but recommended reservation
- Bologna - Florence : 13€ reservation on Frecciarossa high-speed trains