eCheck.Net: Ability to add more billing details in the settings

Can you please add a custom field like an invoice or item key field so we can pass data through it to Authorize.net like we can do in the credit card widget?

It's possible to have custom data mapped to Authorize.net, under the additional gateway settings you may turn on the "Ask billing information to customer" option:

The invoice number field accepts text boxes only and you can add one in case your current form does not have an existing supported field. 

I see these fields working on the credit card form, but when I click on the e-check form it only gives me Billing Address as the only field. The Shipping name, Customer email, Invoice Number and Shipping Address fields are not there. Is there a way to get the same fields to display with e-check as you do for the credit card?

Unfortunatley, currently we only allow billing address within the eCheck.net settings.

I have instead forwarded a feature request to include billing details same as in Authorize.net.

You will be notified here once there is an update.