Capturing values from a Select to the Controller-Codeigniter

Good Morning Galerinha, all beauty?

I'm starting with codeigniter and in the middle of this process I came across a question about the select function. Well, my doubt is to return the value from that select to my controller, so I can do a check from the value. I have a graph and need to control its information by my select. As if my select turned a button, then when I chose the option automatically the chart information change.

select{

    -webkit-appearance: none !important;
    -webkit-border-radius: 0px;
    background-color: #fafafa;
    
    background-position: 100% center;
    background-repeat: no-repeat;
    border: 1px solid #cccccc;
    padding: 0.5rem;
    font-size: 0.875rem;
    color: rgba(0, 0, 0, 0.75);
    line-height: normal;
    border-radius: 0;
    height: 2.3125rem; 
    border-radius: 1px rgb(189, 189, 189) !important;
    min-width: 20px !important;
    
    
    
}

<select class="form-control" id="menuselect">
                     <option>Only me</option>
                     <option>Team</option>
                  </select>