Sometimes you might need to turn off your Google form to stop it from accepting new responses. Perhaps the assignment needed to be done by a specific time and you do not want to allow late submissions. Google Classroom won’t let you do that you have to make that change in Google Forms.
First step will be to go to the responses tab.
Then simply toggle off the “Accepting responses” option.
You can always turn that back on at anytime if you need to.