Hi my iPhone 6s is locked to owner how do I unlock it with out knowing the email and password

If you have bought 2nd hand iPhone, you must contact the seller (hopefully it is the previous owner), otherwise you have been scammed.

Each Apple device is linked/associated with an Apple ID of the person who did the setup.

Activation Lock prevents anyone who is not the owner from using this iPhone.

To unlock the Phone, you need the Apple ID and password of the previous owner, that were used during set up.

So you have to contact the previous owner.

The previous owner has to read -> this Apple article: What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch -> What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support

Then the previous owner has to remove the iPhone from his account, see this Apple article:

Check your Apple ID device list to see where you're signed in

Check your Apple ID device list to find where you're signed in - Apple Support

Then you can sign in with your own Apple ID.

See the following Apple articles:

Activation Lock for iPhone, iPad, and iPod touch

Activation Lock for iPhone, iPad, and iPod touch - Apple Support

How to remove Activation Lock -> How to remove Activation Lock – Apple Support (UK)

• If you need help removing Activation Lock and have proof of purchase documentation, you can start an Activation Lock support request.

👉 Read this before you buy a 2nd hand iPhone.

You can also contact Apple support for help, -> Get Support (apple.com)

You have to show proof of ownership of your product, provide all documentation showing your purchase of the device.

If you do not have additional proof of ownership, contact the reseller. They may be able to provide the original purchase document.

Once Apple receive your proof of ownership, Apple will further review your request and provide an update.

See also -> Keep your receipt after you buy an Apple device

Keep your receipt after you buy an Apple device – Apple Support (UK)

----- 

Ask your money back if possible, perhaps you have bought a stolen iPhone.

If you can't get in touch with the seller, you can't use the iPhone.

If purchased from someone else, there is no way if it has an Activation Lock. A factory reset even if plugged into a computer will not help. The Activation Lock means that the original owner reported it as lost and the phone now is a brick unless you can get the original owners Apple ID and Password.

As Raicya pointed out, you can start an Activation Lock Support request, but I would not expect this to go anywhere. You would have to provide receipt showing original owner and serial number and in most cases the original owner is not the seller. Apple usually will not get involved in these third party sales and I have never heard of anyone getting it resolved in this manner.