To be accepted for a degree or DipHE course, you need at least two A levels or an equivalent level 3 qualification, such as a level 3 BTEC or OCR (possibly with an A level alongside). You also have to have supporting GCSEs or equivalent qualifications. Entry to degrees in clinical subjects can be very competitive, so you may need more than the minimum. Specific subjects (such as science) are often specified. Sometimes entry requirements are stated in UCAS Tariff points.
For other HE courses, such as foundation degrees, entry requirements are often more flexible, but you usually need at least one A level (or equivalent).
If you don’t have the usual entry qualifications, there are other ways to prepare for university. For example, you could take an Access course or opt for a degree with a foundation year (these are usually aimed at students who don’t have the relevant level-3 subjects eg science).
You should always check with the universities you're considering applying to, to make sure that the level-3 course or subjects you are currently studying (or plan to study) are acceptable for entry onto their courses.
For entry to most courses, you will need to show that you understand what the career and the course will involve (eg through relevant work experience). You may also have an interview and perhaps sit an entrance test or submit a portfolio of your work.
If you are applying for an NHS-funded course at university, you'll be asked to show how you think the NHS values apply to the career or course you're considering. The NHS values form a key part of the NHS Constitution. Find out more about the NHS Constitution.