JSFiddle - React, Tailwind, and code Playground
HTML
<form name="form_rens" method="post" action="">
<input name="Radio1" type="radio" value="Oui" onchange=' document.forms["form_rens"].elements["url_1"].value= "essai" '/>Oui<br>
<input id="url_1" class="bord" name="url_1" type="text" style="width:30px" />
</form>