m3ter is an API-first service. When you've created your Meters and their data-collection fields, you can use the Submit Measurements API call to m3ter's Ingest API to submit usage data into those fields:
For more details on this API call, see the Submit measurements API Reference Docs page.
The Getting Started with API Calls provides an example of a Submit measurements API call with code snippets you can copy.
Important! Request Rate and Payload Limits. The Ingest API is designed to handle high request rates and offers high payload-per-request size. However, we impose limits on request rate and request payload size. See m3ter APIs