If you would like disable your File Upload Form and prevent users from uploading files to your Google Drive, you can either password-protect the form or disable the form itself.
Open the Google Sheet that is storing the form responses. Go to the extensions menu and choose
Go to the Deploy menu and choose
Manage Deployments from the dropdown.
Manage Deployments screen, click the
Pencil icon to edit the configuration.
New Version from the Version dropdown and choose
Only Myself under the
Who has access dropdown. Click
Deploy and external users will not be able to access your form.