1) Download the Patch file in Magento commerce. (https://www.magentocommerce.com/download)
2) Copy and Paste the downloaded patch file in Magento root director.
3) Edit the sh file (which one downloaded Patch file),
Line NO 67 : CURRENT_DIR=/d/xampp/htdocs/mage/test_1901/ (Magento root path).
4) Open Git Bash run the sh file use Below command :
sh patch-filename.sh
5) After get success message check the file exist in app/etc/applied.patches.list.
6) Once reverting means use below command:
sh patch-filename.sh -R
7) Also check whether the Patch is installed or not in use below URL :
https://www.magereport.com/
Reference : http://magecomp.com/blog/how-to-install-magento-security-patches/
