For the Feds, they only mention staples or other attaching methods one time...Topic 301 When, How and Where to FileWhen you owe a balance - If you owe tax, you may pay via Direct Pay or enclose a check or money order with your paper return or if you filed electronically, with the 2022 Form 1040-V (PDF), Payment Voucher:Made payable to the United States TreasuryOn the front of your payment include your name, address, taxpayer identification number (SSN, ITIN, EIN), daytime phone number, the tax year and type of form you are filing (for example, 2022 Form 1040).Enclose your payment loosely with your return, do not staple or otherwise attach your payment or Form 1040-V to your return.Do not mail cash with your return.