there is a menu on top of the electrum window.
click on the Wallet option and choose the Seed option. that will open a window asking you for your password. (you can also click on the little seen photo at the bottom right corner of the electrum window)
now enter your password to see your seed, and make sure to write it down on a piece of paper and keep it in a safe place.
Edit (added a screen shot)
![](https://ip.bitcointalk.org/?u=https%3A%2F%2Fi.imgur.com%2FEF0vyBa.jpg&t=665&c=5y_SXEbXroHgWA)