Quick question about Merge Codes in woo commerces order

I am making these custom fields in woo commerce order; such as resvdate.

I am trying to make an automation sending this info in the email but I don't know how to grab these info using merged tags. Anyone know how I get this info in the email?

Other automation plugin(eg. FunnelKit), I can get these info using like this:

{{order_data key="resvdate"}}