Yes! The dimensions between iPhone 6 / 6S, 7 and 8 differ only by 0.1-0.2 mm, which makes the same case fits all three iPhone models perfectly. The same goes for iPhone 6 / 6S Plus, 7 Plus and 8 Plus.
Also, products for iPhone 11 fit on iPhone XR, products for iPhone 11 Pro fit on iPhone XS /X and iPhone 11 Pro Max products fit on iPhone XS Max. Please note, the camera hole for the iPhone 11 models is significantly larger than on the previous models and that the older models' cases should not be used on the iPhone 11 (otherwise the camera is covered).
To see how the case looks on your phone model, please select your model from the product list here.