Open an internet browser. Login to Office 365.
When logged on you'll see your company space in SharePoint, from where you have access to all your company's templates in Office 365 online.
Clik "Documents" marked by the red circle.
Here you can see all files you have saved online.
Click the "Files" tab.
In the Files tab you'll find a ribbon with a Templafy button with the text "Create document".
Click "Create new document" to open and start working with a new company template.
Here you see your company templates arranged in folders according to file type. Choose a folder - in this case Documents.
In the Documents folder choose the template you need - in this case letter.
Fill in the required fields (if any) and choose where you want work with the document. You can continue to work online in Office 365 (if you're working on a tablet this is your only option here) or choose download the document to your computer.
In this case opening the document in Office 365 is chosen, by clicking the button with the Office 365 logo, marked by the red circle.
You now see your document with all personal and company information automatically inserted.