Are you composing in plain text? That is the only way to specify a word wrap length. It defaults to the 80 columns on the original IBM terminal (line wrap at 72 characters) as the spec is that old.

Yes, I'm composing in plain text. I do not have this issue when composing in html. There is no feature to prolong the lines in plain text, right? Or at least I could not find it.

Matt answered

Are you composing in plain text? That is the only way to specify a word wrap length. It defaults to the 80 columns on the original IBM terminal (line wrap at 72 characters) as the spec is that old.

In plain text, if you did not have word wrap, you would have all your text on a single line, until you hit a 'carriage return'.
This can be very annoying to some, no most, almost all readers as they would have to continually scroll back and forth to read any message.
In HTML, text 'flows' on the page. Make the screen area larger and more words appear on the line. Make the screen smaller and the text re-adjusts itself to fit.

edited to show longer word wrap.

Are you composing in plain text?  That is the only way to specify a word wrap length. It defaults to the 80 columns on the original IBM terminal (line wrap at 72 characters)  as the spec is that old.

TB-38.3 Win10-PC