Is eway bill mandatory for this invoice

Yes, you have to prepare E way bill with his car number.

is there any penalty for past practices?

what can be done to rectify what has happened in past? will the supplier get a notice from gst for not creating a e way bill??

Yes, you have to prepare the E way bill complying with the GST laws. In other case there will be a penalty on the supplier also customer in most of the cases. 

For further more detailed information on this topic visit: Complete Analysis of GST E way bill

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