I am new to AI. I have designed a logo on AI when i zoom it on AI to like 8000px or whatever value it shows up perfectly fine no quality loss and nothing. But when i export it in format like png or jped to use it on facebook it becomes pixelated and quality drains out completely. So whats the best way to save logo without quality loss?
In Illustrator, you're working with vector, which means you can resize it to any size and not lose quality. But when you export to bitmap (non-vector) formats like png or jpeg, it only has as much quality as it has pixels. (Here's some more info on the difference between vector and bitmap: http://www.prepressure.com/library/file-formats/bitmap-versus-vector )
To get the best quality when exporting for web, you need to find out what pixel dimensions you need (This is a good resource for Facebook dimensions: https://www.facebook.com/PagesSizesDimensions/), set up an artboard with those dimensions, and export as a png at 72 dpi.