You will be unable to file electronically. Your return will have to be mailed. The IRS may contact you by mail about this. If the person who claimed you did so fraudulently or you don't know who, you may need to report identity theft to the IRS by including Form 14039 in your mailed return. it's under the other tax situations tab. 

or

https://www.irs.gov/pub/irs-pdf/f14039.pdf