JSFiddle - React, Tailwind, and code Playground

HTML

<form>
    <input type="checkbox" id="ch">Да
<input id="sub1" type="submit" formaction="test.php" value="отправить">
<input id="sub2" type="submit" formaction="test2.php" value="отправить2">
</form>

CSS

#ch ~ #sub1,
#ch:checked ~ #sub2{
    display:block;
}
#ch:checked ~ #sub1,
#ch ~ #sub2 {
    display:none;
}