With polkadot.js, users can manage their accounts and sign transactions using the browser plugin polkadot.js wallet. Due to its reliance on the Polkadot apps' user interface to carry out DOT transactions, it is not a fully functional wallet. It also serves as a safe choice that guards users against well-known phishing websites.
Since the extension only manages your keys and allows you to sign transactions, it needs to interact with a UI to show information about your accounts (such as their balance) and make transactions from them. Your options for that include the Polkadot-JS UI (more on this below) or any Web 3.0 app in the Polkadot ecosystem that you choose to connect your accounts to.
The wallet makes it possible to handle and keep DOT, the native currency of Polkadot, which has a variety of use cases within the decentralized blockchain development and smart contract platform.
The Polkadot extension is an account manager and will work in all Chromium-based browsers (Chrome, Brave, Edge) and Firefox.
It is recommended to store your accounts in the extension and not on the Polkadot-JS UI directly.