To send leads in from a lead form you would put the POST URL into the action attribute located in the form tag.

For Example:

<form action="https://leads.leadexec.net/processor/insert/general" method="post">
     <input type="hidden" name="vid" value="1234">
     <input type="hidden" name="lid" value="1234">
     <input type="hidden" name="aid" value="1234">
     <input type="hidden" name="successredirecturl" value="http://exampleform.testsite.com/thankyou.html">
     <input type="hidden" name="rejectredirecturl" value="http://exampleform.testsite.com/unabletoprocess.html">
     .....
</form>

In the example above, the lead would be submitted to https://leads.leadexec.net/processor/insert/general and the system would automatically redirect the user to either the successredirecturl or rejectedredirecturl depending on the result of the POST.

Note: It is important to note that this is not a recommended way of sending leads into the system as the vid, lid, and aid would be publicly visible when the source of the page is viewed.