A footprint was the print left behind by one or several feet. Animal footprints might be known as tracks.
In 2256, Captain Philippa Georgiou deliberately walked in the shape of a Starfleet delta, creating an image in the sand on the Crepusculan homeworld. This was done in order to enable the USS Shenzhou to locate and retrieve herself and Commander Michael Burnham. Upon encountering their own footprints ahead of them, Burnham mistakenly believed they had been walking together in aimless circles and were therefore lost, as she was unable to see the shape the prints made from her vantage point on the ground. (DIS: "The Vulcan Hello")
Finding the footprints of the White Rabbit on the Shore Leave Planet in 2267 convinced James T. Kirk that Leonard McCoy's wild claims had a basis in reality. Later, McCoy noticed a girl's footprints accompanying them, which further cemented his story. (TOS: "Shore Leave")
Kirk ordered the landing party to search for footprints on Lazarus' planet to verify the man's story. (TOS: "The Alternative Factor")
In 2362, Lieutenant Paul Hickman noted that there were no footprints or vehicle tracks on the surface of Tarchannen III, adding that the wind likely blew them away. (TNG: "Identity Crisis")
In 2372, Tom Paris and Neelix found a bootprint on the ground in a cave while trapped on Planet Hell. (VOY: "Parturition")
In 2374, Chakotay determined the route Tom Paris and Harry Kim had taken on the surface of a class Y planet by simply observing their footprints. (VOY: "Demon")