I need to unlock my iphone 6s. I had no access to itunes.

Please define "unlock".

Forgotten passcode? If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support

Carrier unlock? How to unlock your iPhone for use with another carrier - Apple Support

Activation lock? Find My iPhone Activation Lock - Apple Support

Then follow the instructions in the first link I provided.

If you have no computer available with iTunes on it, and you had set up Find my iPhone on the device, you can erase it using the Find My iPhone web app from any computer with a modern browser installed (https://icloud.com).

If you did not have FMiP set up on it, the ONLY option is to use iTunes.