Pass checkout form fields to redirect url / Pass parameter to redirect url

I’m working with wordpress using woocommerce and checkout field editor pro for adding extra fields to the checkout form. Im also using a payment gateway from a local bank.

Right now after the payment is processed the gateway plugin redirect to a set url that make some task like save some info to database and send some extra information to the local bank. The redirect url looks like this like this example.com/?wc-api=paymant_gateway and is set in the woocommerce/payment_settings.

Recently the local bank has requested some extra info that we need to ask the customer in the checkout form and they has told us the only way to do this is to pass the parameters to the redirect url like this example.com/?wc-api=paymant_gateway&field1=value&field2=value&field3=value ,etc.

I have tested it putting the fields manually (hardcoded) in the payment settings and it works it send the extra fields to the local bank

But I dont know how to pass the checkout form values as parameters to the redirect url example.com/?wc-api=paymant_gateway

I have try to look the file that manage the call to wc_api after the payment is processed but I can’t find it because maybe it’t not necessary to pass the parameter to the redirect url but in the file that process the call to wc_api=payment_gateway I could retrieve the order info and retrieve all the checkout form saved values and insert them in the file and in the logic that sends the info to the bank but I still cant find it. I dont know how to retrieve that info tho but I have seen that woocommerce has a built in function to retrieve that information because right now all the info from the checkout form is saved in the order info.

I have harcoded the parameters in the redirect url in the woocommerce/settings/payment settings like this example.com/?wc-api=paymant_gateway&field1=value&field2=value&field3=value and it’s working. It sends the harcoded values to the local bank.

Has somebody done anything like this before?
Thanks