In a sense, there is no difference between tenant farming and share cropping because share cropping is one form of tenant farming. To the extent that there is a difference, you can say that share cropping is the form of tenant farming that is least beneficial to the tenant.
Tenant farming is a system in which people have responsibility for working a specific plot of land, but they do not own that plot. This is different from modern farming where paid workers work wherever their employer tells them to. Instead, each tenant farmer works their “own” plot of land. The tenant is given a place to live as well as tools and seeds as needed. In return, the land owner gets either money or part of the crop.
Sharecropping differs from other forms of tenant farming in that the sharecropper brings much less to the agreement and therefore has to give up much more to the landlord. Sharecroppers do not have their own tools or money. Therefore, they depend completely on the landlord. The landlord takes a large share of their crop in return. A more prosperous tenant farmer wouldn’t need to get as much from the landlord and would have to give up less of their crop. They might even have to do nothing more than paying rent.
So, sharecropping is a form of tenant farming, but it is one in which the tenant has the least control over the crops they raise. It is the worst form of tenant farming from the point of view of the tenant.