All actions are registered in the system regardless of the type of device from which they were made. The actions made both in a mobile browser and a mobile app are taken into account. Actions made from mobile devices are paid at the same rates as actions made from desktops.
If a user clicks your affiliate link on their PC, follows to the AliExpress site, adds a product to the shopping cart, and then pays for it using the mobile app, the order will be assigned to you. If AliExpress confirms it, you will then get rewarded.