Currently there is an implied limit of one Fastpass per day for big rides at Epcot and Hollywood Studios. They call this "tiering" where you can choose just one ride from the Donald group, up to two from the Daisy group, etc.
Which rides are in which group and how many you can Fastpass (v.t.) from each group are subject to change, including more Fastpasses on less busy days.
Paper Fastpasses are completely discontinued now and the kiosks are closed down. If you haven't booked all three of your Fastpass Plus reservations for that day, you can go to (different, electronic) kiosks in the park to book them for that same day.