Is It Possible To Reset A Iphone 6s Without a Macbook

you mean to just restore it to factory settings? Assuming you can get into the phone and use it right now (it's not disabled or anything) then you do not need a computer

How to erase your iPhone, iPad, or iPod touch - Apple Support

NLE_Dream wrote:

How May I Reset My iphone 6s

A Windows PC with iTunes is also an option.

Reset how?