<form action="index.php?action=transfer" method="post">
  <label for="userid">Dla kogo (nazwa uytkownika)</label>
  <input type="text" name="username" id="username" 
           value="<?=$username?>" readonly="readonly">
  <label for="points">Ile punktw</label>
  <input type="number" name="points" id="points" 
           value="<?=$points?>" readonly="readonly">
  <input type="submit" value="Potwierd" >
  <input type="hidden" name="userid" id="userid" 
         value="<?=$userid?>">
</form>