So if I want to hold is better to keep my Bitcoin in a wallet or in an exchange ? What's the difference ?
for short answer: keep your bitcoin in a wallet that you own/control its private key(s)
if you store in an exchange, you will lose it when anything bad happens to that exchange
for more thorough detailed explanations read the stickied as mentioned by
mjglqw Always read pinned threads and read around before asking questions or advice because chances are, your question/request has already been asked in the past. Topic: [General] Bitcoin Wallets - Which, what, why?:
https://bitcointalk.org/index.php?topic=1631151.0