Push notifications are used to engage your potential customers. There is no limitation as to who can implement push notifications and who can not.
As far as you provide regular and new updates, you can integrate push notifications to your website and mobile. Companies from across the world are using push notifications today.
The most popular industries that use push notifications are eCommerce companies, Job portal companies, News and Media companies, Blogging platforms, Ed-tech companies, Entertainment sites like live streaming, and so on.