A 1:1 coaching takes place between Coach and Coachee (two people), while a Workshop takes place between Coach/Trainer and a group of people or a team. Whether an individual Coaching or a Workshop are the better option depends on the initial Ask.
As a rule of thumb:If an individual is struggling within a well-functioning team then a 1:1 Coaching is the better starting point.If a team is broadly having difficulty then a team coaching is the better starting point.