The different UK work permit categories or Tiers are mentioned below:
Tier 1 visa: The Tier 1 visa, or the Entrepreneur or UK Innovator visa, is specifically for highly skilled individuals like investors or business people. The Tier 1 visa is a special category visa for Non-EU candidates that are exceptionally talented and are willing to invest at least £200,000 in the UK.
Tier 2 visa: The Tier 2 visa is a work visa that allows transfers of skilled immigrants with a job offer or sponsorship to the UK. The candidate with a Tier 2 visa must score at least 60 points and is required to have an employment offer in the country.
Tier 3 visa: The Tier 3 visa is for low-skilled workers to fill job vacancies when there is a demand.
Tier 4 visa: The Tier 4 visa is a type of student visa for international students who wish to pursue higher education in the UK with two years to look for jobs in the country.
Tier 5 visa: The Tier 5 visa, also known as the Temporary Worker visa, is for individuals who can work in the UK temporarily. Charity workers, sportspersons, or Government exchange schemes are eligible for the Tier 5 visa.