If you are able to send files from your Mac to other devices and unable to receive the files from them even after pairing, the most likely reason is your bluetooth sharing isn’t turned on.
Turn on bluetooth sharing on MAC OSX?
Turning bluetooth sharing is very simple.
Open preferences panel and select sharing and then select enable bluetooth sharing. You will now be able to receive files via bluetooth on mac.
You can find the screenshots for the process below.
Note: Either turn off bluetooth sharing when you don’t need it or make sure you have “Ask What to Do” selected for both receiving files and when other bluetooth devices try to browse your Mac. If you are not careful, people can use this to install spyware or other malicious software or get access to your personal files.