If you want to store the preferences in client side ( assuming nothing needs to be secured ) you can simply collect your data from your form's onSubmit action then create a json data with it and save it in localStorage. something like;

<form onsubmit="save()">......</form>

<script>
   function save(e) {
       e.preventDefault();
       var prefs = {};
       var inputs = document.querySelectorAll('input, select, textarea'), i;

      inputs.map(function(item) {
              Object.assign(prefs, {[item.name] = item.value});
      });

      window.localStorage.setItem('prefs', JSON.stringify(prefs));
   }

   window.onload = function() { 
       var prefs = JSON.parse(localStorage.getItem('prefs'));
       Object.keys(prefs).map(function(key) {
           document.querySelector(`[name=${key}]`).value = prefs[key];
      }) ;      
   }
</script>

it is untested, but should give you an idea

Where do you want to save these preferences? in browser? server?