From BitPay, Inc.:
Copay is a secure bitcoin wallet platform for both desktop and mobile devices. Copay uses Bitcore Wallet Service (BWS) for peer synchronization and network interfacing.
Copay is a true bitcoin wallet, not an account service. Secure your personal funds with multiple signatures, or just one.
Take security into your own hands and avoid trusting third parties with your savings. Like a joint-checking account, your Copay wallet can have multiple users. To send money, the group approves each transaction.
Manage shared funds with friends and coworkers. Share a wallet with your child and introduce them to bitcoin. Copay makes sharing a wallet simple and secure.
The Copay app securely stores multiple, distinct bitcoin wallets, allowing both business and privacy-conscious users to keep funds carefully separated.
Manage personal, business, and testnet wallets easily, all without leaving the app. Copay uses hierarchical-deterministic (HD) wallets, allowing for secure in-app wallet generation and backup.