facing problems with inserting data

You mean the "Send Now" button - right?

I don't see the "savesms()" method anywhere. While looking for it I notice that you have a controller and model that are both named "sms". You probably shouldn't do that. Perhaps name the model "sms_model".

The next problem of note is with using sms_form() with the $.post(... call. $.post(... expects data to be returned by the server but you make a redirect() instead. That's wrong. Echo some data in reply instead. Here's one way but it is presented without knowledge of what happens in "savesms()" so it's maybe not the best solution.

PHP Code:

public function sms_form()
    {
        $save = array(
            'sender'           => $this->input->post('sender'),
            'recepients'       => $this->input->post('recepients'),
            'body'             => $this->input->post('body'),
            'sendscheduletime' => $this->input->post('sendscheduletime'),
        );
        //if savesms() returns false when saving fails then use
        echo $this->sms->savesms($save) ? "Success" : "Fail";
    } 


Looking more closely at your <form> I cannot find an <input> for either 'sender' or 'sendscheduletime'. So your $save array will have NULL values for those two items.

Just to make sure the "Send Now" button 'click' event is being handled do this test.

Code:

$("#SendSMS").click(function () {
    event.preventDefault();
    alert('Send SMS Clicked');
   // var postData = $('#SendSMSForm').serializeArray();

   // $.post("<?php echo base_url('sms/sms_form') ?>", postData)
           // .done(function (data) {
             //   alert("Data Loaded: " + data);
          //  });
});