Per the IRS:
Form 8453 is required to be filled out and mailed to the IRS when one or more of the forms below are included in an e-filed return.
Form 3115, Application for Change in Accounting Method. Form 5713, International Boycott Report. Form 8858, Foreign Disregarded Entities Information Return.
If you are filing your tax return using an online provider, mail Form 8453 to the IRS within 3 business days after you have received acknowledgement from your tax preparation software company that your return has been received and accepted for processing.
