How to attach files to an Email from Sharepoint Online

To attach a copy of a document to an email in Sharepoint online:

Save and close the document you want to send.

In Outlook click on New Email

In the new email click on the Attach File icon.  This will bring up a dropdown menu, of the last few files you opened

Select the file you wish to send and this will attach the file to the email.

Alternatively 

At the bottom of the dropdown list click the Browse Web Locations and choose the Sites - Story Homes option

This will bring up a list of recent folders you have had open in Sharepoint

Select the folder you want to open and this will open a new window where you can select multiple files that you can then attach to the email.