revision:
The maxlength attribute can be used on the following elements: <input> and <textarea>.
With respect to <input>, the attribute can be used on elements that accept string type value.
<textarea maxlength="number"></textarea>
<input maxlength="number"/>
number: it is the maximum number of characters allowed in an element. Its default value is 524288
<form style="margin-left:3vw;" 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>
<textarea style="margin-left:3vw;" rows="4" cols="50" maxlength="50">
Enter text here...</textarea>