This is excellent addon by ModulesGarden and something we and our customer love and use it every day. Our customers have started using this for their every day use (storing their entire password repo) and they simply LOVE this. It is very well encrypted & we use it extensively to share login details with customers through PasswordManager rather than over email or tickets. Highly recommend this addon for anyone using WHMCS!
Works great and can be customised as required! The support is extremely quick to address any issues. Highly recommended!