Run the software and connect both or more iOS devices to Mac. iTransfer for Mac will detect your devices automatically and show the libraries of the devices at the left sidebar. Now you can transfer files between the two iOS devices.
Choose any kind of files under LIBRARY and hold Command/Shift key to select certain files, then right-click the selected files and choose Transfer to > iPhone.
Or check the square checkbox beside Name to select all files, then click the transfer button . Then set the target device to “Transfer to List: iPhone” in the pop-up window and click Transfer Now button.
With the above done, a pop-up window will show the transfer process and just wait it done.