Each character is effectively a number, which the computer uses the font to translate into a glyph. Arabic is no different in this respect; each arabic symbol is a number that the font translates into a glyph. You're not seeing an 'Arabic font', you're seeing the same font rendering Arabic characters. (If the current font doesn't have a glyph for the given character, you'll see something along the lines of � or an empty box.) If you're just pasting text into the chat, you're just pasting the characters used, not the font. Even if your players had the Gallifreyan font installed, it wouldn't help, because nothing is telling their computer to render the text in Gallifreyan. Character sheets (and, by extension, rolltemplates in the chat) can try to tell the user's computer to use some specific font, however that requires either all of your players having the font installed or hosting the font somewhere (and there aren't really solutions for hosting arbitrary font files outside of running your own server, which is how several fonts on sheets I've authored are available). Additionally, if the font is hosted somewhere, Roll20 pipes the file through a proxy, and the proxy is (currently) not running over https, which means the user's browser will block the font file until the user explicitly allows it. Further, having a custom character sheet (and thereby having custom rolltemplates) requires that the campaign creator has a Pro subscription.