Save as a compress library is particularly helpful if you wish to send your EndNote library to another person. This is because this process will generate only one file which can be easily sent via cloud drive or attached in your email.
Click on File.
Select Compress Library (.enlx)...
Select With or Without File attachments, All References in the Library, Selected Reference(s), or References in Group/Group Set, then click on Next.
An .enlx file is generated for backup purpose. You can also send the .enlx file to your collaborators for sharing purpose.
You can learn more about creating an archived copy of an EndNote library from the official video below: