Merchant account necessary?

[Gregdelof]

Hi everyone,

I'm preparing my muse. I'm going to sell an E book and monetize the website with Google Ads and a Clickbank affiliate product.
I'm using Yahoo Store and a Wordpress architecture.

My questions: Do I need a merchant account? And to open a legal business?
Or can I use something like Paypal and linking it to my personal bank account?

Is the pdf file of the e-book can be automatically sent when an order is processed with these solutions or shall I plan to do it manually?

Many thanks in advance for your answers, not being American, this part is still a bit blury for me...

Best to all of you! :-)