Yes they can. I would like to state first though, that one should always use certified mail to send anything to the IRS.  That way you get the green card back, which is proof that they received it.  However, since COVID and the seven-month IRS shutdown, we do not let our clients send money to the IRS by mail.  They are losing mail every day and often, even after receipt, they do not process it for several months.  It simply is not safe to mail money to the IRS. There is a better way.  The IRS has a service called Direct Pay.  It is web based and is available 24/7.  Your payment is taken directly from your bank account. This service provides instant confirmation of payment and your bank account information is not retained.  It has five steps: verify identity, enter payment, review payment, electronically sign and record the transaction.   To use the service go to www.irs.gov/Payments/Direct-Pay.  There is also a way to use a credit card, but a fee is associated with that.