How to create a real time Checklist with multiple checkboxes edited in realtime by multiple users?

How can I create a Checklist containing multiple checkboxes shared and updated in real time by users who use the app?

Is it better to upload and reload a file to a cloud with the information about the checked boxes and automaticly reload it once the file is modified?

Even better if the app could give an alert that the checklist has been modified by another user.

Is it possible any easy suggestions?

Thank you guys