If you’ve finished a degree-level course or higher in the UK and have a good record with your education provider, you can apply to switch from a student visa to a Graduate route visa. This used to be called the PSW (Post-Study Work) visa. You must apply for the Graduate visa from within the UK, and you can only do this while you still have permission to be in the UK as a Student. Once you switch to another visa, you can’t qualify for the Graduate route anymore.
The Graduate visa allows you to stay in the UK for at least 2 years after finishing your course, or 3 years if you completed a PhD. It’s important to know that the Graduate route itself doesn’t lead to settlement (Indefinite Leave to Remain), but the time you spend on this route counts towards the requirement for settling in the UK based on 10 years of continuous residence.