Student or Learner
I know that N1 is correct, how about the other two?
1. I want him to open the door.
2. I would want him to open the door.
3. I would like him to open the door.
3 is fine and is the same as 1 (if a little politer). You could make a case for 2 but it would have to be a hypothetical and either in response to a question and/or part of a bigger statement.
What would you want Jack to do if this room caught fire?
I would want him to open the door and let everybody go to safety.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.