Official notification about your account status will arrive via private message from /u/reddit. That account and other admin accounts will have their usernames displayed in red on reddit.com and the official apps. A Snoo icon or a red "[A]" (for "admin") should appear next to the username, like these examples:
If there is an email address attached to your username, you will also receive notices at that address from @reddit.com or @redditmail.com addresses.
If you receive an email from Reddit about your account that seems suspicious, do not click any links in the email and forward it to admins at email@example.com for verification.