own social media agency

hi.
i'm thinking about starting my own social media agency. i would then specialize in little things like press releases, instagram growth, facebook / twitter and youtube marketing. does anyone here know how to best build everything together? which payment processors are best to use? stripe? are there ready-made scripts for shopify, for example? i would want to work all over the world. many thanks for your help.

i want to start that too
please if u have any courses or advice don't forgot send it to me