加拿大网签的确认信

请问一下各位，网签提交后收到确认信，上面第一句话是什么意思?要邮寄一份护照复印件过去吗？？？
When will CIC contact me?
You are expected to provide a COPY of your passport with your electronic application. If CIC needs your physical passport, CIC will request that you submit it to our office. CIC will also contact you if we require additional information, documents or an interview.