This can be easy depending on how close you are with that person. Often it would be a lot better if he has given out hints that he likes you too.
If you are in the dark and have no clue if he is as interested as you are, this will probably be a bit of a challenge. Nothing we cannot figure out a way for though.
It is better to approach him while you have a clue on the type of person he is. The aim is for you to be able to tell him how you feel not to get you embarrassed.
You are brave? Text him
If you are not brave, consider texting him and let him know how you feel about him. Do not complicate things by saying a lot. This is the time you tell him that you like him and what your intentions are towards him. You can even opt for a voice note, this can even be a better option because he will be able to detect how nervous you are or how you giggle after saying his name. These are some of the things he might find cute and would score you some points.
Meet up with him
If this makes you feel better and you want the chance to just see his facial expression when you let him know, do this. Meet up with him, but at a place where you will both be comfortable. There can be people around, but it should not be those who will be interrupting you while in the middle of a conversation. Be open to him and do not hold anything back. If he doesn’t like you, it is fine. You did something that you have always wanted to do and have no regrets.