I got 2:3 degree in which uni I can apply for bar at law? In uk.
Do you mean a 2.2 or a third? In either case you have almost no chance of becoming a practising barrister in the UK without at least a 2.1 in law or in another subject.
If you have a qualifying law degree you can apply to various providers of the Bar course. If you do not have such a degree you will first have to obtain a Postgraduate Diploma in Law. Each course lasts a year. Each course is expensive.
In either case you would have to obtain a pupillage after the Bar course. It is very difficult to do this and you would be competing aginst people with firsts, high 2.1s, LLMs and BCLs, often from highly competitive universities.
Without a 2.1 you would likely be wasting your time and a lot of money trying to become a barrister in the UK.