<div class="form-group">
                            <label for="exampleFormControlFile1"><p>4 : Media * :</p></label>
                           <p> <input type="file"  name="file_name">
               </div>

public function create(){
        $config['upload_path'] = './uploads/';
        $config['allowed_types'] = 'jpg|png|jpeg';
        $this->load->library('upload', $config);
        $this->upload->do_upload('file_name');


        $file_name=$this->upload->data();
        $data=array(
            'institute'=>$this->input->post('institute'),
            'category'=>$this->input->post('category'),
            'content'=>$this->input->post('content'),
            'relavent_authority'=>$this->input->post('relavent_authority'),
            'multimedia'=>$file_name['file_name'],
            'created'=>date("Y-m-d H:i:s"),
        );

            $data['id']=$this->Question_model->add_data($data);
            $data['authority'] = $this->Question_model->getAuthority();
            if($this->input->post('share')=="yes"){
                $this->load->view('header',$data);
                $this->load->view('questions/share',$data['id']);
                $this->load->view('footer');
            }
     }