Returns are able to be electronically filed if the taxpayer or spouse (or any of their dependents) has an Individual Taxpayer Identification Number (ITIN) instead of a Social Security Number (SSN). If the dependent does not have a SSN or ITIN, the taxpayer can either e-file without the dependent and file an amended return later, or apply for an extension using IRS Form 4868 Application for Automatic Extension of Time To File U.S. Individual Income Tax Return.

Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.