What are the advantage of a fighter jets than a helicopter?

There's no comparison between the two. They're totally different tools. This question is like "what is the advantage of a hammer over a washing machine?"

Fighter jets are good if you want to fight other fighter jets or drop bombs.

Helicopters are good if you want to transport personnel or supplies, observe combat or (if you have an attack helicopter) fight tanks.

Helicopters and jets serve different operational requirements.

Helicopters are better suited for insertion/extraction, ground support, ground attack, SAR, Anti-tank, anti-personnel roles

Jets are better suited for Air Superiority, anti-installation, AWACS, reconnaissance, stealth bombing, long-haul roles