Google Now is disabled for some countries. Here is how to enable it.

First long press on empty area in home screen, go to Settings → Accounts & privacy. Click on Google Account and sign out.

Next go to Phone Settings (the one in your app drawer), then go to Apps → swipe to ALL and find Google Play Services. Click on it and select Disable, accept all warning. If it says it is a device administrator, then go to Settings → Security → Device administrators and disable Android Device Manager (you can enable it later).

Now sign in to your Google account again (long press on empty area in home screen → Settings → Accounts & privacy → Google Account → sign in).

Finally enable Google Play Services again and update it. Also enable Android Device Manager back if you need it.