Your bitcoin exists as an entry on a global public ledger. Your bitcoin is never literally “in” your phone, or your wallet.
What you DO control is the private keys that allow your bitcoin to be moved or spent. Your private keys are kept in your phone app, in the program on your desktop, in a hardware wallet, or even simply written on paper. That said, it is easier to say ‘my bitcoin is in x’, or ‘I moved my bitcoin to y’ in general conversation.
Learn to take custody of your bitcoin keys, and don’t leave significant amounts of your bitcoin controlled by the exchange you bought it on. “Not your keys, not your coins” is an important maxim to remember!
I don’t ever leave any amount of bitcoin on an exchange for long. The best exchanges, like BullBitcoin in Canada, don’t even let you have that option, you must send your btc to your own wallet as part of the purchase process. This is the way.
Bluewallet is an excellent wallet for your iPhone or Android. It’s simple enough for beginners, but has many advanced features you can start to use once you are more comfortable with bitcoin.
When you open a wallet, you will be prompted to write down 12 words as a backup (“recovery phrase” or “seed phrase”). It’s extremely important to keep these 12 words secret and secure. Do not type them into any device connected to the internet. Do not take a picture or screenshot with your phone. Write them down on paper and then keep that paper in a safe place.
**Anyone who knows the 12 words has access to your bitcoin.**
Note that some bitcoin wallets have 24 word recovery phrases instead. Same rules apply – keep them secret, keep them safe!
Coldcard is what I use and recommend when it comes to hardware wallets.
A hardware wallet is a device that contains your private keys and is not regularly connected to the internet like your phone or desktop computer is. This makes a remote hacking attack impossible. In order to steal bitcoin keys kept on a hardware wallet, the thief would need physical access to the device AND know the PIN to unlock it.
Once you have an amount of bitcoin that you would feel uncomfortable carrying around in your wallet or purse if it were cash, it’s time to consider getting yourself a hardware wallet.