u003ca href=u0022https://www.adp.com/u0022 target=u0022_blanku0022 rel=u0022noreferrer noopeneru0022u003eADPu003c/au003e is currently the largest payroll software service provider. The company has over 900,000 clients who use its payroll services and is available in over 140 countries. Other payroll software with a vast client base includes u003ca href=u0022https://www.paychex.com/u0022 target=u0022_blanku0022 rel=u0022noreferrer noopeneru0022u003ePaychexu003c/au003e and QuickBooks Payroll.