"View only" account are public addresses, imported without signer keys.
Importing such accounts allows you to view its balances, connect with apps, simulate transactions and more, but you cannot control them and cannot sign transactions or messages.
Their import status can be changed at any time, by adding their signer keys (recovery phrase/private key) or connecting it with Hardware Wallet (if they are hardware wallet accounts).
You have two options to do so.
First one is trough the account selector from the Dashboard. Open the drop-down menu and click on "Add account". Then select the import method, depending on the signer keys you have.
Second one is ti open "Settings" -> "Accounts" -> click on the settings menu of the account and select "Manage keys". Use the "Import" button and select the import method, depending on the signer keys you have:
