HTML

html input autofocus

<form action="/action_page.php">
  <label for="fname">First name:</label>
  <input type="text" id="fname" name="fname" autofocus><br><br>
  <label for="lname">Last name:</label>
  <input type="text" id="lname" name="lname"><br><br>
  <input type="submit">
</form>