I'm new to this Bitcoin stuff and discussing it with friends. Somebody said, if you "have bitcoins on your phone" and you lose your phone, you also lose your bitcoins.
Is this true?
No, not necessarily. In fact, if you actually follow the instructions given by most wallet software, you won't lose your Bitcoin.
When you first setup a Bitcoin wallet, most modern wallet software will walk you through making backups of your wallet (which are not stored on your phone). Most will also force you to click through multiple dialogs of "I understand that not backing up means I can lose all of my coins" if you try to skip the backup process. If you have a backup, then you can restore your wallet on a new phone or on a computer with a different wallet software. If you do not have a backup, then yes, you will lose all of your Bitcoin.
Alternatively you could use a web wallet where the information necessary to spend your coins are stored on the internet with a third party. In this case, if you lose your phone, you won't lose your coins so long as you remember your login credentials. But I wouldn't recommend using a web wallet as they can cause many other security and privacy issues that can result in you losing all of your coins.
mm.. for example if you have coinbase account where there is web interface as well, there you don't lose nothing..
but if you have only app on phone and all wallet data is there then yes, this could happen..
Very Secure • Your private keys never leave your device. UberPay's Multicoin Wallets using one master key
In this case, i think you will lose coins if you lose your phone..
Same with computer software where your wallet data is stored on your personal computer without backups you could lost them as well..
And there was another type, where your wallet data is stored on paper, so in that case if you lose that paper, you lose your coins..
Summary: Don't lose your staff :)
The most important thing is that your app allows to show/export a seed phrase. A seed phrase is combination of 12 (or more) words made of natural language, which lets you restore your key(s) any time with many other wallets.
I own a company for restoring bitcoins, and I keep telling this to my customers.
Best regards, Andy