Jameis WInston is on his one visit with the Tampa Bay Buccaneers right now, as first reported by Adam Schefter of ESPN. Schefter notes that Winston's visit will be very "Glazer-centric", so it seems Winston will have to convince team ownership that he's the guy they should draft.
The visit will take three days according to Adam Schefter, but Rick Stroud and other local beat writers claim it will take only one day. League rules only allow Winston to spend one day at the team facility, where they can run him through workouts. The team could still meet with Winston outside of the facility, which would be a gray area, per Gil Arcia. So presumably he'll talk to some coaches and other folks outside of the building.
Today will be absolutely crucial for Winston, though, because he has to convince everyone that his off-field issues were just immaturity and that he's grown past that immaturity. Because if the Bucs are going to draft him with the first overall pick, they have to feel they can trust him.
Marcus Mariota is expected to go through a similar visit, presumably later this month.