Credit card number? Via email? Really?!
This is not my idea… Client wants data sent to email.
Also I see that one form is somehow dynamic. There is an option to add items and number of items is not predefined. User can add one item, click “add more” and then additional row appears. This is some javascript (jquery). There is no problem with it, I jsut do not know how to do this in WP.
In terms of a plugin, I’d suggest http://wordpress.org/extend/plugins/contact-form-7/ Not sure it will work for your “dynamic” form though, That may have to be custom coded.
But I strongly recommend that you warn your client about the dangers of sending credit card numbers via email. It’s incredibly insecure. As a general rule of thumb, you should never send anything by email that you wouldn’t send on the back of a postcard.
So then – if I would like to code this form manually, how to properly do this?
Imagine I have one file form.php which contains form to be filled in and processing this form (sending by email or saving to db, no matter). But how to ingerate this in WP?
It should be somehow integrated with Pages (so Page1 is my custom form1 and Page2 is my custom form2). I have no idea how to do that.
how to properly do this?
You would effectively have to create your own custom plugin.