Office 365 community member Releve068 asks, Do I need to add an Exchange Online subscription to a Small Business subscription? Rather than give a quick answer, it is a good opportunity to demonstrate the interactive Office 365 Service Descriptions comparison page. View the video below for a quick demonstration.
There are many features in the Office 365 online services and it's easy to be overwhelmed by large tables, such as this one for Exchange Online. The Office 365 Service Description Comparison page is a great way to see different plans and their features, setting filters to display the information you are interested in. This tool should help you decide on the subscription that is best for you, displaying what services and features are included in each of the online services.