Why do newly minted ERC-20 tokens not show up in a wallet?

Question

When minting a new token and sending it to a friend's wallet, the tokens seem to vanish. What is happening and how to make them visible?

Answer

The tokens are not lost, they are just 'invisible' because wallets do not automatically scan the blockchain for new coins. To fix this, you must manually add the token's smart contract address to the receiving wallet.