What if I have a 2nd w-2 to file but I didnt receive it yet? Can I file the one I have now and the other later?

NOOOOOOO ..... you MUST wait for all your forms before you file.   Do not be in such a hurry ... the IRS will not even process any returns until at least 1/27 so you CAN  and SHOULD wait. 

NO.   ALL of your W-2's must be on the SAME Form 1040.  WAIT until you have all of them.  The IRS is not accepting returns until January 27, so filing now would not result in an early refund anyway.

@xmasbaby0   Nice use of font size ... this cannot be stressed enough.