PDF Merge: Combine PDF is a versatile app that is perfect for anyone who needs to send multiple files in a single email. This is an extremely easy-to-use app that does not require any special knowledge to use. It is very user-friendly and intuitive, so even people who have no knowledge of using applications can get it to work in a matter of minutes. The application has a modern and intuitive user interface, which makes it even more appealing. 

The app allows you to drag and drop the files so that you can easily organize them. It also provides you with an option to send them via email, which is a very easy and convenient way to send multiple files to a single recipient. The application is free to use, and it is extremely easy to install and use.