A view-only wallet can only see which incoming transactions belong to you. It can not spend any of your Monero, in fact it can't even see outgoing transactions from this wallet. This makes view-only wallets particularly interesting for
You can create a view-only wallet from any existing wallet.
Open an existing wallet or create a new one using
monero-wallet-cli. In the wallet, type
viewkey to display the wallet's address and secret viewkey. Type
exit to close the wallet.
Next, create your view-only wallet by typing
monero-wallet-cli --generate-from-view-key wallet-name. The last argument will be your new wallet's file name. You will be prompted for
Standard address and
View key by the wallet. Paste in your original wallet's address and secret view key. Next, enter and confirm a password for your new wallet and you're done.