I put all my btc in coinbase, is it safe?

With custodial wallets being vulnerable to hacks, you can never guarantee the safety of your funds. Therefore, you should search for a better alternative wallet in which you have full access to your funds and comprises a good security feature. Read and follow the initial phase indicated in the post to convey the main idea. Nevertheless, I will suggest reading these threads to gain a better insight into the types and differences between cryptocurrency wallets.

[1] [General] Bitcoin Wallets - Which, what, why?
[2] [GUIDE] Bitcoin/Cryptocurrency Wallets and it's risks [UPDATED: 10/8/2018]
[3] Custodial vs. Non Custodial Wallets - "Not your keys, not your coin" Explained.

Thank You for your advice..