If you think that you need some fancy applications to tranfer files from your laptop/computer to mobile, than you are wrong.
All you need is Python
NOTE: Your laptop and your mobile phone should be on same network
Let's get started
Open your terminal and execute this command.
If you are using Python3:
python -m http.server
If you are using Python2:
python -m SimpleHTTPServer
When you will execute this command it will create a HTTP server on your local machine.
Type <IP_Address>:8000 in your mobile browser to access the files in the directory where you ran the above command.
If you don't know your IP than follow this steps:
Go to System Preferences -> Network-> You will see your IP address there
Suppose your IP address is 192.168.0.1 then open mobile browser and type 192.168.0.1:8000 to access the files.
I saw an app that generates the QR code to access the file over LAN. I don't remember the name, but I think it's not that hard to write your own. That would be much simpler to get the file rather than typing 192.168.whatever in your browser and then finding the file.