There is a real myth that surrounds Bitcoin or any other Cryptocurrency wallets. The myth is that you are actually storing the Bitcoin on your computer or mobile device. This is a lie. The amount you have in Bitcoin or any other cryptocurency is never stored on your computer or mobile device, rather, it is stored on the actual Blockchain under your encrypted address.
Your wallet has private keys that unlock a virtual safety deposit box that allows you to send the coins that are on your LEDGER to anyone you choose. The wallet is truly a private key to unlock the lock of that virtual safe to send the coins as you choose.
Understanding that the data you would have to store on your device would be astronomical. Think about it you would have to store all of the entire Blockchain as well as your actual coin data. This is why your coins cannot be counterfeit, because the actual coin info is never on your wallet.
Understanding that the coins are never on your actual device, it shows that the wallet developers truly do not understand this because they actually tell you if you loose your phone, you loose your coins. That we know is a lie. If you back up your coins you will always have them.
DESKTOP WALLETS
To properly back up a desktop wallet, once it is fully synced up with the Blockchain and once you have encrypted it, go to c:\user\yourcomputer usr\AppData\Roaming and look for the wallet.dat file. Copy this dat file onto a USB drive which you can remove from the computer. Once you have this stored in a safe place, if your computer ever crashed you could download the wallet get it syncedup then copy your dat file to replace the one that is there.
MOBILE WALLETS
The mobile wallet can be backed up to an external source as well this way if you ever loose your phone the backup can be retrieved in order to retrieve the coins you have.
Most other wallets such as Electrum, EXODUS and others have what is called a seed. These are groups of words that you can write down in a book in order to put your wallet on another device if need be.
Understanding that the coins you have earned are never truly in your wallet, you can understand why it is important to have a complete backup of your wallet so you will never loose your coins.
