set maximum length of input code example

Example 1: input maxlength

<form action="/action_page.php">
  <label for="username">Username:</label>
  <input type="text" id="username" name="username" maxlength="10"><br><br>
  <input type="submit" value="Submit">
</form>

Example 2: html input max vs maxlength

<input type="text" maxlength="4"/>