When you file a joint tax return both spouses must sign the return. When you file electronically each spouse signs using a personal identification number (PIN). This self-selected PIN can be authenticated with the prior year adjusted gross income (AGI) or the prior year self-select PIN.
If you take your return to a tax preparer, both spouses will be required to sign the return using their PINs. According to the IRS, the tax preparer may ask you to sign Form 8879, IRS e-file Signature Authorization, authorizing the preparer to enter your PINs in the electronic tax return.
If you prepare your own taxes, one spouse may have both spouses’ W-2, 1098 and 1099 forms and any other information necessary for preparing the tax return. One spouse may normally handle the preparation of the return. It may be that one spouse has more experience and is accustomed to preparing the return, is more inclined to handle tax return preparation, or has the time to do it. There may be tacit agreement on the part of the other spouse as to the information reported on the tax return.
But regardless of how the tax return is prepared, and the level of involvement of the spouses in the preparation process, when it comes time to sign and file the return, both spouses should be aware of what is being reported on the return and sign it using their individual PINs.
When one spouse normally handles the preparation and filing of the couple’s tax return, he or she will have the prior year’s adjusted gross income number and could select a PIN for each spouse. The return could be filed without the other spouse’s active involvement. But a signature using a PIN is still a valid signature and has consequences. In the case of a tax return, signing using a PIN means that you have examined the return and are declaring that it is true, complete and correct.
If the tax return is prepared correctly and both spouses are aware of the information reported on the return, there generally would not be any problems. But both spouses are jointly and individually responsible for the tax determined on a joint return. If problems develop down the road, and there were errors or misstatements on the return, both spouses could be held liable, including the spouse that was not directly involved in preparing the return.
There is innocent spouse relief available under certain circumstances that can relieve one spouse from liability for the tax owed on a joint return. But innocent spouse relief must be applied for and there is no guarantee that it will be granted by the IRS.
The best practice when preparing and filing your joint return electronically is for each spouse to review the return once it is completed, and to sign the return by selecting and entering their own PIN.
Signing an Electronic Tax Return, IRS
Signing Your Electronic Tax Return, IRS
Who Should Sign Your Tax Return? Yahoo Voices