I didn't say to FILE your tax return manually. Just to manually enter the W2. Or are you trying to prepare the W2s for your employees to efile to the IRS? How are you trying to "upload the pdf"? I don't think you can do that. You either import the W2 directly from your employer or take a picture of it. No pdf involved.
https://ttlc.intuit.com/community/entering-importing/help/how-do-i-import-or-enter-my-w-2/00/26253
