Where did Giuliani get the 1.8 million figure? A simple googling shows more than 1.8 million mail-in ballots being returned in days leading up to November 3rd. Also, there's this:
https://electproject.github.io/Early-Vote-2020G/PA.html
Now, before you decide to act like a bunch of conservative cucks and question the source, yes, the Pennsylvania secretary of state is a Democrat, but you lost the right to argue that as evidence of invalidity when you decided to reject what was said by the Georgia secretary of state, who is a Republican.