By default, LibreOffice automatically corrects many common typing errors and applies formatting while you type.
To quickly undo an automatic correction or completion, press Command Ctrl+Z.
To turn off most AutoCorrect features, remove the check mark from the menu Tools - AutoCorrect - While Typing.
Click the Replace tab.
In the AutoCorrect list, select the word pair that you want to remove.
LibreOffice automatically draws a line when you type three of the following characters and press Enter: - _ = * ~ #