Do I enter my EIN# if it was not obtain in the year my taxes are due for?

[cliff15]

I started the process in 2016 but did not receive my EIN until 2017

[DawnC0]

You do not have to, but you can.  As long as you didn't pay wages in 2016, it won't matter either way.  

A tax ID number is not required if you operate a sole proprietorship or an LLC with no employees, in which case you would simply use your own Social Security Number as a tax ID. But you must obtain an EIN if you are a sole proprietor who files pension or excise tax returns.