Basically, I am trying to update the date in "Tax Rates Updated" any time the "Tax Rates" field is changed and saved. I have managed to catch when the Tax Rates field has been changed but I do not know how to change the date inside of the "Tax Rates Updated" field of the post.
I got the issue. It does not work on your site because the field text_to_input is registered and saved first. If you want to update the field text_to_update, please drag and drop it above the field text_to_input. Like this https://share.getcloudapp.com/d5u6JvQz