Protected
<input type="radio" name="seguro" id="desgravamen" class="formulario__input " >
<label for="desgravamen">Desgravamen</label>
</div>
<input type="submit" name="submit" class="formulario__submit" action="controlador" id="ap">
In order to validate the "required" property, it must be inside a form. In this way, when executing the submit, it executes the validation of all its fields. Greetings!
<form>
<input type="checkbox" required>Check required
<button type="submit">Submit</button>
</form>