Indian Citizen Living In Us Need Business Visa To Philippines?

I’m an Indian citizen living in the US for the last 1 yr (I’m a legal worker with L1 visa). I need to travel to Philippines for Official purpose. Do I need a Philippines visa before traveling (or) can I get a On-Arrival stamping provided I’m having all the required papers (Invitation letter, company docs). If visa is reqd, whats the process like, I stay in Bay area, California.