i deleted me email account on iphone 6s. how do i restore it?

Hello,

Choose your account

1. Go to Settings > Mail > Accounts > Add Account.
2. If you see your email provider, tap it to add your account automatically. If you don't see your email provider, tap Other to add your account manually.
   
3. Tap Next. Mail will try to find the email settings and finish your account setup. If Mail finds your email settings, tap Done to complete your account setup.

More info here:

Set up an email account on your iPhone, iPad, or iPod touch - Apple Support

Ok you said an email account. There is no way to delete Mail from Settings as shown in my picture. Do you mean the Mail app if so follow the steps:

Restore a built-in app that you removed

1. Go to the App Store.
2. Search for the app. Make sure that you use the exact name of the app. Find the correct name of built-in apps.
3. Tap to restore the app.
4. Wait for the app to restore, then open it from your Home screen.

Remove built-in Apple apps from the Home screen on your iOS device with iOS 10 - Apple Support

Ok is your device up to date? It should look like this:

Yes exactly what deggie has said.

So you are talking about the App correct?

Here's the link again:

Remove built-in Apple apps from the Home screen on your iOS device with iOS 10 - Apple Support

OK, so you did not delete an 'email account'. You completely deleted the mail app. You should be able to re-download it from the app store.

The correct name of the app is Mail, not apple email app, as it showed in the link Gus provided.

Okay which iOS are you on?

Settings > General > About > Version, include the numbers in parentheses.

Can you provide us more information. Can you post some pictures. Please blur out any personal data.

Do you have any profiles installed?

Settings > General > Profiles(under VPN)

You said you deleted your email account. The steps I have provided is the way to add emails.

Then restore iOS using iTunes.