Cool Font Generator: Copy and Paste Cool Fonts

No, and that's actually why they work. Fontly converts your letters into special Unicode characters that look like different fonts but are ordinary text. That's why you can paste them into places that don't allow font changes, like an Instagram bio. Nothing is installed on your device.

Because every device draws characters using its own installed fonts. Your styled text arrived intact, and your friend's device simply renders it with different designs, or shows squares (□) if it's older and missing those characters.

No. Fontly is an online tool that runs in your browser, so there's nothing to download, no app to update, and no account to make. It behaves the same on a phone, a tablet, and a desktop, which is the easy part of using Unicode characters instead of font files.