If you are coming to the UK as a visitor, you are allowed to stay for up to 6 months in most cases. The Visiting the UK section of the UKVI web site explains the different types of visitor and what you are allowed to do as a visitor.
If you intend to stay here for longer than 6 months, you need to look at the Working, Studying or Partners and families sections of the UKVI web site.
The University (International Office/Human Resources) determines which category is appropriate to individuals coming to the UK under one of these routes based upon the criteria outlined. We do not allow individuals to choose the category which they think is appropriate to them.
Categories of University Visitor