Zapier is a workflow automation tool that integrates with thousands of apps from partners like Google, Salesforce, and Microsoft, allowing users to create secure, automated systems for their business-critical workflows. To connect Microsoft To Do and Google Calendar, a Zap needs to be created, with the Microsoft To Do app used as the trigger. The user must authenticate with both apps using bank-level encryption, then supply a previous task completed in order to finish setting up the trigger. Once set up, an action is created that sends data from Microsoft To Do to Google Calendar, specifically creating detailed events for new tasks, including summary, description, due date and time fields, which can be customized by the user. With this setup, new tasks in Microsoft To Do will automatically create corresponding events in Google Calendar.