If I buy an SSL Certificate, is this trusted in Apple without installing cert file in iOS? I created an app for iOS for a company and I want to distribute this app ad hoc over the air.

In iOS 7 and greater, I need an https site to install this app.

I created my own certificate locally and I must install my cert file via email or a direct link on iPhone to Trust this certificate and then I can install my app.

I want to know: if I buy an SSL certificate from legal seller like godaddy or geocerts and set it to my own website, do I need install a cert file on the iPhone or not?

My company's site is offline and not connected to internet.
Purchasing an SSL certificate will not require any further configuration on the device, regardless of whether this is from a 'standard' Certificate Authority.

If the certificate is purchased from a standard Certificate Authority, this provides the additional benefit of verifying the company being represented by the domain, but this is tangental to the actual HTTPS requirement by Ad-Hoc distribution.