The law seems pretty clear that this is totally allowed and the last ditch Republican effort to block it (only in Fulton county which has a heavy Dem lean, even though other counties also were accepting ballots) is just more GOP horseshit.
“The lawsuit was filed late Friday and cited a section of Georgia law that says ballot drop boxes cannot be open past the end of advance voting, which ended Friday. But state law says voters can deliver their absentee ballots in person to county election offices until the close of polls at 7 p.m. on Election Day.”
A Georgia judge has rejected a Republican lawsuit trying to block county election offices from opening on Saturday and Sunday to let voters return their mail ballots in person.
apnews.com