Hosts

Make sure these hosts match the hosts declared at the top of the manifest file.
Required. Specifies a collection of host types and their settings.

Manifest Version 1.1 - VersionOverrides

The Hosts element in the versionoverrides section will override the Hosts element above.

<OfficeApp> 
<Hosts> 
   <Host Name="Workbook"/> 
</Hosts> 

Name - Mailbox, Workbook, Document, Presentation, Database, Project

<VersionOverrides> 
   <Hosts> 
      <Host xsi:type="Workbook"> 
         <DesktopFormFactor> 
         <TabletFormFactor> 
         <PhoneFormFactor> 
      </Host> 
   </Hosts> 
</VersionOverrides> 
</OfficeApp> 

Host - MailHost, Workbook, Document, Presentation, Database, Project
FormFactor - DesktopFormFactor, TabletFormFactor, PhoneFormFactor