The Satisfactory Map Repository (SMR) provides a place to share your creations in the form of entire maps.
There is currently no such method in the game itself. The only way to send someone a map is to upload it to some random file hoster or send via instant messaging applications.
This website provides a place for you to manage your maps. You can upload maps and make them visible for everyone or keep it private as a form of backup. Others can see your public maps and download them. An easy to use API is provided to integrate the service into almost every application.
SMR is free to use. No account or registration is needed for viewing/downloading maps.