1. Once you have downloaded the .zip file to your computer you need to extract the files using your favourite zip extraction program.
2. Upload modules folder to whmcs folder.
3. Navigate into Setup > Addon Modules and Activate Email Verification Extended
4. Now Click on Email Verification Extended Configure Option and Give Access Control as per your need and save the setting.
5. If sometimes it does not work then make sure you have enabled attempt to load all files from Settings -> General Settings -> Others tab

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