I am developing an ios app for a client and would like to know that when I go for the $99 developer program I can post the app and get all the help but what about when I want to provide everything to the client will they have to get another apple id and sign up again for the $99 program or will they have to go for some other program and can the app be transferred from my account to theirs, it is going to be a free app, so if I manage it in the clients name is that okay. the app developed by should come as the "company's name"
Yes, you can transfer apps between developers' apple id. See apple's official documentation:
You can now transfer qualifying apps to another account — useful in cases of an acquisition or asset purchase. When you transfer an app, it will remain available on the App Store or Mac App Store, all ratings and reviews will carry over, and users will continue to have access to future updates.