Warning: Do not download Electrum from another source than electrum.org. Verify GPG signatures.
Free and Decentralized
Electrum is free software.
Released under the MIT License.
Anyone can run an Electrum server.
No single entity controls the network.
Safe
Your private keys are encrypted and never leave your computer.
Forgiving
Your funds can be recovered from a secret phrase.
Instant On
Electrum is fast, because it uses servers that index the Bitcoin blockchain.
No Lock-In
You can export your private keys and use them in other Bitcoin clients.
No Downtimes
Electrum servers are decentralized and redundant. Your wallet is never down.
Proof Checking
Electrum Wallet verifies all the transactions in your history using SPV.
Cold Storage
Keep your private keys offline, and go online with a watching-only wallet.
Multisig
Split the permission to spend your coins between several wallets.
Add-ons
Electrum supports third-party plugins: Multisig services, Hardware wallets, etc.
Released under the MIT Licence
source : https://electrum.org/#home