It’s like a keyboard attached to the printing part of a printer. As you type, the letters get printed on the paper, rather than typing onto a screen and then printing all at once.
Yes, I know. It was a joke. On the fact that the archived question was about something nobody cares about anymore.
Clearly not a very funny joke.
Well, I’d lay odds that someone is going to come across the practice sentence “Now is the time for all good men to come to the aid of the party” at some point and wonder just where it came from, GuanoLad.
Probably a Doper, too.
I know it was a joke. If I’d thought it was a serious question, I would have called you a chowderhead or somethin’. 
While perhaps “nobody cares about [typewriters] anymore”, the computer keypad does happen to use the same QWERTY keyboard…
… And don’t dismiss typewriters so fast. My mother-in-law still uses one. God knows what will happen when it needs repair, but she’s not about to change to anything as ephemeral as a passing fad, like computers.
Hey Dex I’ve got a “brand new” word processor/typewriter. I’d have to check out the make and model, but it was like $300 new. Well, it’s actually about 8-10 years old now…but it’s practically never been used (Maybe fifty pages typed on it). Lemme know when your MnL is ready.
She might even start liking you again… 
A lot of offices still have typewriters. People find them convenient for typing single labels or envelopes.
And for filling out pre-printed forms.
(But they are becoming scarce, it seems.)