I need a software recommendation

So here is my situation. I am a contractor with many contractor friends. I want to start doing lead gen for them. I need a software where I can make landing pages and collect lead info. I also need a place where I can write out payments and invoices for clients. But since I will be doing it for my friends, I want to be able to change the branding very quickly between the pages. Or if I can have them write out estimates but send it through me. I will be marking up their work 10% and taking that as payment for generating leads. Any ideas for best software for that?