What is a Paper Wallet?
A paper wallet is an offline mechanism for storing bitcoins. Unlike fiat currency, there is no physical representation of a bitcoin or most other cryptocurrencies. Rather, "wallets" which are used to store digital tokens are usually software programs that help to facilitate updates to the blockchain ledger when transactions are made. Paper wallets are different from so-called "hot wallets" because they operate separately from the Internet. However, they still do not store physical bitcoins; the "paper" quality of these wallets refers primarily to the method of access for the cryptocurrency owner.
Benefits of a Paper Wallet
Physical wallets were long considered one of the safest ways to store bitcoins. If properly constructed, and provided that certain precautions are taken, it will be nearly impossible for a hostile user to access your bitcoin holdings. A paper wallet is considered an extremely secure way to keep bitcoins safe from cyber-attacks, malware, etc. A paper wallet involves "printing" and storing bitcoins in an offline mode. But it's important to remember that it’s not the bitcoins that are being printed out like regular currency. It's the information stored in a bitcoin wallet or digital wallet that gets printed out. The data appearing on the wallet includes the public key (wallet address), which allows people to transfer money into that wallet, and the private key, which gives access to fund spending. Thus, bitcoins themselves are not stored offline, but the important keys are stored offline.
This form of 'cold storage' confers enormous security advantages. The user is more or less invulnerable from cyberattacks and malware because it is simply not possible to access a user's private key via those avenues. Of course, the safety of these physical documents cannot be entirely guaranteed either - if a would-be hacker discovers the location of your paper wallet and physically steals it, they can access your Bitcoin holdings. Some users hide or disguise the paper wallet. The paper wallet should also be protected from physical damage - if the keys fade and can no longer be scanned, the user will never again be able to access the Bitcoins sent to that address. Even using the incorrect type of printer (non-laser printers can allow the ink to run, for example) may damage the paper wallet.
You can also check balance of any BTC wallet from this app by scanning or entering the BTC address.