Gmail's Inbox Actions provide a convenient way to complete tasks embedded in email messages without having to open the message. To use Inbox Actions, your domain must have a consistent history of sending at least 100 emails per day to Gmail addresses over the last couple of weeks, a low spam complaint rate, and only setup actions for transactional emails. You need to register with Google and make a request for your domain to be whitelisted before implementing Inbox Actions, which can involve markup, testing, and securing action requests. The guide covers everything from schema.org to in-depth examples of each type of action, providing a comprehensive resource for those looking to get started with Inbox Actions.