Hello rolifuchs, the device has a web browser installed. As with other eBook readers, it is quite slow, but it works. It can be used to download and use books purchased in bookshops (e.g. buchhaus.ch) or books borrowed from libraries.
We also have a Kobo, but I have never tried to download anything via WIFI, but you can copy all the data (EPUB, PDF, etc) via USB cable. You can also access Google Play Books.