Google has made it easy for you to submit the data related to your building that can become a part of the Google Maps indoor maps now accessible from their Android mobile app.
You can submit the related data in different formats to Google. The company mentions that they accept photos of floor plans, blueprints, or directories of a floor.
After you have uploaded this data, you can align them with the satellite imagery of the building in Google Maps.
Google would do the rest of the processing. Once the data is processed and approved, it would be available from their mobile apps.