She cannot apply for a SSN unless she is physically in the US and has permanent resident status. However if you do want to file the return with her, you can fill out a form W7 and apply for a ITIN. Income taxpayer identification number. However, you do not have to choose to file the return with her. You can file return separately from her – be careful, return filing status is MFS not single. She is not a US person and not obligated to file a uS return.
