Email Hosting with online Archive (Microsoft Exchange).

Exchange Online Plan 2 includes everything that is part of Exchange Online Plan 1 but also incorporates the ability to have an unlimited inbox capacity. Unlike Exchange Online Plan 1, Plan 2 allows you to have an unlimited cloud based archive. Both plans have a restriction of 50GB for the inbox but with Plan 2 you can stores as much information in the online archive as you want, whereas Plan 1 is limited to 50GB in total between inbox and archive.

Exchange Online Plan 2 also incorporates advanced features such as the ability to place mailboxes on 'legal hold' to preserve their contents irrespective of what actions users take. Plan 2 also incorporates Data Loss Prevention (DLP) that provides the intelligence to ensure valuable information is not sent outside your organisation. For example, you can create a document template that will be checked when people send an attachment to ensure it doesn't match. 

Company who has lots of email and would like to have unlimited of archive would go for this Exchange online Plan 2.

You may consider to add a Dollar more to have extra features like OneDrive for Business (1TB Cloud Storage), Skype for business (Video Conferencing), Microsoft Teams, Yammer with Office365 Business Essential plan.

* All images shown are for illustration purposes. Actual product may vary due to product enhancement. *