Office365 iOS
Office365 apps are available from the Apple App Store, this allows you to use the Microsoft Apps to connect to mail, and other collaboration tools.
More information on downloading them to your iOS based device e.g. iPhone, iPod or iPad can be found from the following URL
https://products.office.com/en-us/mobile/office-mobile-apps-for-ios
The default Mail app does not list Office365 Groups which you may be a member of, so if you wish to see these in as folders in your mailbox then use the Outlook app to connect to your Mersey Weaver mail account.
When connecting your Outlook mail app to your account, ensure you choose "Exchange" not "Outlook".