<div class="custom-control custom-switch">
<input type="checkbox" class="custom-control-input" id="customSwitch1">
<label class="custom-control-label" for="customSwitch1">Toggle this switch element</label>
</div>
<button class="btn btn-outline-warning m2-3 disabled" type="submit">Отправить</button>
$(function() {
if($('#customSwitch1').is(':checked')) {
$( 'input[type="submit"]' ).removeClass( "disabled" );
} else {
$( 'input[type="submit"]' ).addClass( "disabled" );
}
});