I would like to obtain a telephone number, how do I do it?

I want to get a new phone number, but I’m not sure how to go about it. Do I need to contact a specific operator? Are there any online options for choosing my number, or do I have to go to an operator? I’d also like to know about the different types of numbers available, such as local numbers, international numbers and virtual numbers. Can you tell me how to go about getting a new phone number?