Hi Sahil,
CA SAM is designed to take the outset and address the compliance requirements from the license perspective, i.e. it's important during implementation that you follow the same approach. So it would be recommended to begin with outlining the following for any product/suite (e.g. Microsoft Office in your situation):
- HOW is the product/suite licensed (license metrics, etc.)?
- WHAT information is required in order to be able to compare the acquired product use rights against the usage of the product/suite and as such prove compliance?
- WHERE can this information be discovered and collected from?
For Microsoft Office there are predefined signatures and/or recognition rules, so if your organization is purely licensed by the number of devices on which Microsoft Office is installed (the answer to 1 above), you will need to collect software inventory from all devices in the organization that tells if Microsoft Office is installed (the answer to 2 and 3 above) in order to prove compliance.
An example from the Master Catalog for Microsoft Office 2016 Professional Plus: