Can I change the button location?
Yes.
You can specify the button should go on either the bottom-left or bottom-right of the page. The bottom-right is the default. You can specify this by adding a bit more code when you add the Callback Request embed code on your website. You should add the following:
<script>
let CR = {
floatButtonSide: "left",
};
</script>
<script defer src="https://callbackrequests.com/embed/button.js?0.1.3"></script>
If you want to use your own custom button, see the Can I use my own button? FAQ.