JSFiddle - React, Tailwind, and code Playground

HTML

<script>
    function agree() {
     b = document.getElementById('btn');
     c = document.getElementById('checkbox');
    
	 b.disabled = !c.checked;
}
  
</script>

<table width="800" height="50" border="0">
    <tr>
        <td width="500" height="42"> 
            <input type="checkbox" name="checkbox" id="checkbox" value="checkbox"  onClick="agree();"/>
            <label> I agree to the Terms and Conditions. <br></label>
        </td>
        <td width="800" align="left">
            <div>
                <input id="btn" type="button" name="Button" value="Submit"  disabled="disabled"/>
            </div>
        </td>
    </tr>
</table>