System Requirements - Windows
Instruction Link -https://getcomposer.org/download/
Using above link you will get the composer.exe file for Windows and when need to run composer.exe to install, it will ask for the path of php.exe which you can find in your WAMP directory whichever you are using.
In windows, PHP automatically comes with WAMP even you can download it according to your requirements of PHP Version and also you can switch PHP versions easily with the help of WAMP.
NOTE:-The WAMP for windows are not available with pre-installed or pre-enabled Mailparse Extension hence download Bitnami WAMP from below-given link.
It comes with the support of Mailparse Extension so you just need to uncomment the Mailparse Extension from the php.ini file of the specific version you have enabled and after that, you just need to restart Apache Server.
In Windows when you are using Bitnami WAMP it already comes with Imap Extension you just need to uncomment the Imap Extension in php.ini file of the specific version and restart Apache Server, it will work as expected.