Normally products like Office are updated through Windows update. This needs to be enabled in the Windows update settings before it will show any of the non Windows updates.

If the checkbox for "Give me updates for other Microsoft products when I update Windows" is grayed out and unselectable in Windows 10 then try the following:

First add a version to the OS layer and activate the layer. You can use one of the runipkwin10.cmd scripts to do this. (This can likely be done in the Office layer but this was not tested)

Finalize the OS layer

Now add a version to the Office layer.

Go to run, type gpedit.msc

Navigate to Computer Configurations--Administrative Templates--Windows Components--Windows Update

In the right hand window select 'Configure Automatic Updates' -- Set it to 'Not configured' Click apply.

Now Click on Start--Settings--Update & security--Windows Update, Click on Check for updates, Once it finishes saying 'Your device is up to date', Click Advanced options.

'Give me updates for other Microsoft products when I update Windows' should now be available.


Source for this fix:
http://answers.microsoft.com/en-us/windows/forum/windows_10-update/cannot-set-option-to-include-office-updates-in/30d14904-9799-46d1-9279-d2c537a0235a