The electronic postmark is not generated until *after* your e-filed tax return has been accepted. There is a physically separate electronic postmark for each individual tax return you file. One for federal, and one for each state. But again, those pages are only generated *AFTER* the e-filed return is accepted by the respective taxing authority the e-filed return was submitted to.
So if you downloaded the PDF to early it's highly probable the postmark printout will not be there. Just download the PDF again and look for it in the newly downloaded PDF file.
For colleges, many of them want a copy of your tax return that *physically* has your signature on it in ink. So after you print it, sign it and date it with the same date as the electronic postmark.
