When you create a workflow, it obviously creates a task and sends an email to the participant(s) that they have a task.
However, minor issue - in Outlook 365, the email message states "Click the Open this task button" to open the task. In regular Outlook, this 'button' appears in the toolbar when you open the mail message. However, in Outlook 365, this button is nowhere to be found!
This means a training issue - when you are using workflows that send emails, the link to the task is missing so you must tell your users to navigate to the site itself, open the appropriate Task List and respond to the task.