When working in the Windows environment, you need the environment variables to add the path where the composer bin is, as you can not find it, that's why you get the error
Steps:
Right click on equipment
Properties
Advanced system configuration
Click on environment variables
Inside system variables look for the option that says Path
Add the following route
C: \ Users \ UserName \ AppData \ Roaming \ Composer \ vendor \ bin
Adapt that equivalent path to your pc, close the cmd, reopen it, if there are no more details; write composer and you should return the composer commands and recognize the command
Remember each route that you put in the system variable separates it by ; that is, after the last value that appears in that route, it places the; and paste the equivalent path to the one I put above