If you need to check supplier details whilst working with a Purchase Order, you can do so by clicking on the little (i) button next to the supplier's name near the top of the Purchase Order screen:
This will open a pop-out window showing the contact details you have specified in the Supplier record:
From the pop-out window, you can click on the Email Address or Web Address links to open a new email to that address, or to open that webpage, in the default email and web browsing apps on your device.
