PS5 does not come with its own web browser application, however you can use websites indirectly. One of the ways is to visit Settings User Guide/PS5 Help and follow links within the guide to open a browser window. Alternatively, messages, notifications, or content of a game can be clicked on links, giving access to a simple browser interface.
It is not as good as using a full browser and therefore complicated browsing is normally more convenient using a personal computer or a phone.