There are parts of the world where you can get online and on Facebook/whatsapp without even having “internet”. If you pay for Internet, you get access to other websites as well.
Some places you get internet, but you’re limited to 3-4 “basic” sites unless you pay for it. Facebook/Whatsapp is often one of those basic sites. Or was.
Now which of those is available worldwide?
There are parts of the world where you can get online and on Facebook/whatsapp without even having “internet”. If you pay for Internet, you get access to other websites as well.
How does WhatsApp work without Internet?
Some places you get internet, but you’re limited to 3-4 “basic” sites unless you pay for it. Facebook/Whatsapp is often one of those basic sites. Or was.
So there’s Wi-Fi or cellular network, but just filtered?
Not one of those but XMPP (once upon a time called Jabber) is available worldwide.
So is Matrix.