For a Citizen who has an international spouse it is required to attach a statement to the tax return, that states that we want to consider both resident. How to attach?

[DoninGA · Accepted solution]

The tax return will have to be mailed, attaching the statement to the mailed tax return.

See this TurboTax support FAQ for the procedure to print and mail a tax return using the online editions - https://ttlc.intuit.com/questions/1944348-how-do-i-print-and-mail-my-return-in-turbotax-online

Your spouse would only need to report their income if you were filing your tax return as Married Filing Jointly, applying for an ITIN with the tax return and you would be providing a statement with your tax return that you want your Nonresident Alien Spouse Treated as a Resident.  See IRS Publication 54 Tax Guide for U.S. Citizens and Resident Aliens Abroad pages 6 and 7 - https://www.irs.gov/pub/irs-pdf/p54.pdf

[DanielV01]

Best way is to mail-in the return.  Technically speaking, you can file a statement electronically.  But if the IRS doesn't see it for one reason or another, you may end up getting a letter to clarify.  While mailing in the return is a slower acceptance than e-filing, it is still effective for certain situations (and sometimes required).  This is one situation where this is the case.