The hotel's page under “Popular amenities” → “All amenities” → “Services and amenities” lists information about WiFi availability. If WiFi is available, the password can be requested on site, for example at reception.
Most often, using WiFi is free of charge for guests, and if there is a separate charge, this will be indicated in the hotel's “Conditions of accommodation” and “Additional information” sections on the hotel's page. Please review this section before making a booking.
When you go from the hotel page to the booking page, click on the “Important, please note” button under the room rate. It will be possible to further explore the accommodation conditions there.