there are several kinds, check out a website some will give total privacy, some reduce heat and still provide some privacy
Amazon has a good selection and quick delivery, take a look here:
Home Depot and Lowes also have some at their stores but not as big of a selection as Amazon.
As Marlene responded, there are different levels of coverage, all depends on you purpose.
Easier and cheaper buy dollar store clear contact paper cut size WET the window with water apply contact paper you can move it around since it’s wet! I used this in Fl for my front door panels that people would always peek in
here are some great ideas from hometalk: