It usually arrives by email. It doesn't come directly from the author of the virus. It usually comes from someone you know who already has the virus. The virus is sent automatically. The sender is unlikely to have sent it to you deliberately.
Various versions exist.
Any email can contain a virus. You should certainly never open an attachment you were not expecting. The email has an attachment which it asks you to open. If you double-click the attachment, you get infected. If you simply delete the email, you will not be infected.