Deleted questions are visible to high rep users even while they are deleted. What's more, they can be undeleted. If this happens the authors will still be the same as before, and those people will gain the reputation again (that they lost when it was deleted.)
For a new user, deleting bad questions or answers is a dangerous thing to do. Because the questions or answers don't really go away, they continue to count against their authors in an unpublished score of quality. If this score gets too low, the user is prevented from asking any more questions or providing any more answers. (There are separate question and answer bans.) The only cure for the ban is to improve existing contributions, but low-rep users can't find deleted questions or answers to improve them. The best advice is not to delete early questions that are poorly received if there is any way to improve them instead.
Some users delete questions once their problem is solved. This is very selfish behaviour. The question and its answers may be of help to other users later. As an incentive to leaving the question in place, the asker can continue to get reputation from the question for years to come. Accept an answer to let others know it worked, and then leave the question.
If the reason you want to delete the question is that you are embarrassed by your former lack of knowledge, you can ask to have your account dissociated from the question. It will not be deleted, but it won't be connected to you any more. And if you accidentally posted sensitive information it is possible to have that information removed (even from edit histories) if you contact the team.