1Password for iOS integrates with Password AutoFill. Once enabled from the Passwords & Accounts Settings, you'll be able to fill and save passwords, without ever opening the 1Password app.

As you sign into accounts on iOS apps, you'll notice a key symbol with Passwords above your iOS keyboard. To save a Login, tap the key symbol and Create Login. Enter your username and password, or tap Generate New Password to automatically create a strong password. When you're done, tap Save & Fill. Going forward, you'll see your username above the keyboard, making signing in, in the future, easier than ever.