Well, one could write a whole book about the application process. So, I don't know how could we help you. There are tons of things to consider, and you didn't tell us much.
I think you need to do some basic stuff first, like checking PhD programs' websites to see what they require or expect. And then ask more specific questions, and with more information so people can better understand your situation and plans.
And, just like when we're doing a PhD, people may provide some guidance, but you will need to do a lot of work by yourself. Different people follow different strategies when applying, have different criteria to make decisions, have different resources, etc. We can share some of our experiences and knowledge, but they may not apply to your case.
By the way, my MBA and my MS were in Finance, but I'm doing a PhD in Marketing. There are things that only very specific people would be able to really help you with, depending on factors like the country you intend to do a PhD and your specific research interests.