MADISON, Wis.--(BUSINESS WIRE)--Esker, a worldwide leader in document process automation solutions, is pleased to announce the launch of an enhanced service which will help companies comply with mandates for e-invoicing when working with public authorities throughout Europe. Following the April 2014 directive on e-invoicing and public procurement (2014/55/EU), vendors will be obligated to send e-invoices to public administrations in all European countries by 2020. This directive will deliver si