First... why do you want to do that or think that it is necessary?

edit... based on reviewing your other post - I'm 'guessing' you want to attach details of a one-to-four properties 1031 exchange. Screen 4.1, down to e-file PDF/Miscellaneous (left side, last one).   Click the 'button' that says PDF Attachment, then the one 'Attach PDF'.   Browse to where the file is on your computer.