Many taxpayers have encountered individuals impersonating IRS officials – in person, over the telephone and via email. Don’t get scammed. We want you to understand how and when the IRS contacts taxpayers and help you determine whether a contact you may have received is truly from an IRS employee.
The IRS initiates most contacts through regular mail delivered by the United States Postal Service.
However, there are special circumstances in which the IRS will call or come to a home or business, such as when a taxpayer has an overdue tax bill, to secure a delinquent tax return or a delinquent employment tax payment, or to tour a business as part of an audit or during criminal investigations.
Even then, taxpayers will generally first receive several letters (called “notices”) from the IRS in the mail.
Read the complete IRS article at: https://www.irs.gov/uac/newsroom/how-to-know-it-s-really-the-irs-calling-or-knocking-on-your-door