Its actually very simple. All you need to do is to ensure you peruse the whole option on the electrum software in other to see the private key. You can equally just scan it .  When you are on Electrum on the upper panel, just locate wallet then you see private key click on it then you see the keys attached to each wallet address where you can then copy to where you taking it too.

Another way to go is to click on addresses locate the address you have btc before the fork, then right click to choose the option of private key, this is quite simple because it will not only show the private key to that address but also the bar code which you can scan. If your are using coinomi mobile wallet, its very much easier.