If someone else intends or has claimed the Taxpayer as a dependent, the Taxpayer must check the box marked "Check here if the Taxpayer can be claimed as a dependent on someone else's return". This check box can be found in the Basic Information > Personal Information > Additional Personal Information section of your account.
Married Filing Jointly
If you are filing a return as Married Filing Jointly and someone else intends to claim either the Taxpayer or the Spouse on the return as a dependent, you must check the same box for either the taxpayer, the spouse, or both.
Note: In general, someone else should not be claiming you or your spouse (if you are filing Married Filing Jointly) as a dependent unless your return is only a claim for a refund and there would be no tax liability for either you or your spouse if you filed separate returns.