Hello.
All you need is create fields with name with brackets (<input … name=”data[]” />)
Unfortunately, CF7 can’t parse construction like ([text data[] id:data]), so you have to add brackets via JS.
Example:
[text data class:data] <a href="#" class="add">+</a>
jQuery(document).ready(function($){
$('.data').attr('name', $('.data').attr('name') + '[]');
$('.add').on('click', function(e){
e.preventDefault();
$('.data:first').clone().val('').appendTo('form');
});
});
The message will contain your data separated with commas.
This is a simple solution without any validation.