On which day of the week was no manna found on the ground?

Answer: The seventh day

Israel gathered manna for six days, twice as much on the sixth; on the seventh day some went out but found none.

“For six days you may gather, but on the seventh day, the Sabbath, it will not be there.” Yet on the seventh day some of the people went out to gather, but they did not find anything.”— Exodus 16:26-27 (BSB)