The SigningHub for Word add-in installation that is done on a Microsoft Office 365 account, is called an Office 365 installation. This installation type is available on both the trial and paid accounts of Office 365. It is used when you need to send the Word documents for signing from your Microsoft Office 365 account.
Installation prerequisite
Microsoft Office 365 account should be created, and Word Online or Word 2016 should be configured in it.
Microsoft Office 365 Installation
You can install the SigningHub for Wordadd-in from the Office store on your Office 365 account. However if the direct access to the Office store is disabled in your organisation, you can create an app catalog site and place the Office manifest file there. In this way, your enterprise users can access the app catalog site (on premises store) to
install the SigningHub for Word add-in on their Microsoft Office 365 accounts.
To install SigningHub for Word on your Microsoft Office 365 account: