Is it possible to share an arXiv article before it is announced?
Until the article is announced, it does not have a publicly viewable URL.  It can only be accessed from the account of the submitter.  So you cannot effectively share your paper until it is announced in the regular arXiv mailing.  However, since that announcement should be within at most two business days (unless your paper gets flagged for special treatment, because of extensive evidence of plagiarism or some other problem), it should not hurt you too much to wait for the announcement.