Muslims call the word Allah the "grand word". It is often written in a certain way, i.e., with the dagger Aleph (الألف الخنجرِية) - the vertical dash on top of the second letter ل . This sign kind of a trademark of the word Allah I would say. How do you produce that?
Many people use the standard fonts that come with MS Windows or MacOS when they want to type in Arabic. So they will end up using Times New Roman or Arial. But there are good alternatives.