metric for gas reading

what metric do I provide my gas in KW or M3

Unless it’s an old imperial meter (cu ft × 100), a gas meter reads the number of cubic metres.
Bulb will apply a formula, taking into account the prevailing calorific value of the gas supplied, to convert cu metres to kWh for billing purposes.

@gkw Your meter is m3. kWh reads for your gas meter will never be used or submitted to the suppliers.