Sheffield is a hilly city; this matters more than tourist guides usually admit. From the station up to West Street or down to Kelham Island is fine, but the longer cross-city walks are a workout.
Supertram — Sheffield's tram network runs east-west and out to Meadowhall, useful for reaching Crystal Peaks, Halfway, Middlewood, and Hillsborough.
Buses — A comprehensive bus network covers the suburbs; First South Yorkshire and Stagecoach are the main operators. A day ticket is good value if you plan to do several trips.
Walking and cycling — The city centre is walkable. Cycling is harder thanks to the hills but a network of cycle paths runs through the Don and Sheaf valleys.
Taxi apps — Uber, Bolt, and the local City Taxis app all work in Sheffield.