For people working from home, depends on the company - most will send a message to the laid off person's personal email and immediately lock the person out. If they don't have a personal email on record they'll just lock them out and send a letter in the mail or something.
Yep, pretty shitty behavior. They do it to keep people from retaliating or organizing a protest or starting drama or whatever.
To me the really weird thing is the way people talk so positively about getting fired on linkedin.
It varies from company to company, and often based on your relationship with your boss and coworkers, or just how the higher managers want to handle things.
In my country
There are 200+ countries, and 200+ ways of doing things. Not everywhere is like home.