Musafir is a traveler, but after covering how much distance is a person called Musafir? I've been searching for this everywhere but the distance varies everywhere.
A musafir is the one who is travelling in a distance that is equal or exceeds two marhalah (apprx. 86 ~ 90 km) in one way direction.
If lets say a town is 45km and he travelled forth and back, which is 90km, that cannot be considered as a musafir.
If you are talking about the rukhsah on the Salaah (for example shortening zhuhr and asr from 4rakaat to 2 rakaat) a person must be musafir and the purposes of the journey must not something that is sinful.