We have a unique situation (at least for me, first time seeing this).
We have a web form where accountants can fill in requests and that part is taken care of. But after their login we redirect them to a third-party website where we need more information from them. The process is crazy right now since we have to give our account login info to all people filing with us. So is there a way in PHP or any other solution where we can after that form on our website auto login with our information to that third party website in a way that our credentials are not visible to the users using the service?