Send trade to steam using js/php?

Question

PHP

You need to send an offer of exchange in the incentive, through the official api. I need to replicate the functionality of one extension for a site selling game items, where the exchange of items is carried out using an extension that itself sends a trade offer and ensures that it is accepted. But I can’t find a method with which I could implement such functionality using only the steam api key (without login and password)