There are various ways in which you can come to the UK to study. For example, if you are under the age of 18 years, you may be able to apply under the Tier 4 (Child) category. For those applicants over the age of 18 years, applications can be made using the Tier 4 (General) category.
If you are looking to finalise preparations for your study course in the UK, you may be able to come to the UK as a Prospective Student. If you want to study for a short course, you can apply as a a Student or Child Visitor.