The recruiting manager or selection panel chair will contact their successful candidate(s) first.
If that’s you, congratulations! If you accept the offer, you will be told what the next steps are. If you need some time to consider the offer, ask for it, but be prepared to agree (or be given) a reasonable deadline for your decision.
In more senior posts, or if there have been a lot of candidates, you may be invited for a second-round interview.
If, unfortunately, you aren’t offered the position: try not to take it personally. This doesn’t mean you did badly or that you’re ‘not good enough’, just that another candidate was a better match to the role.
You should ask for feedback, or accept it if it’s offered. Sometimes this feedback can be vague or unhelpful, but sometimes you can get some useful pointers on how to improve next time.
You can also reflect on your own performance at interview:
If you believe that the selection process was unfair at any stage – for example, if you think you were at a disadvantage because of your age, sex, marital status etc. – you have three months less one day to make a complaint.
Citizens Advice offers help on what to do in this situation.