If you want to transfer files, folders or text in a "user friendly" way you can use applications such as Localsend, it allows you to transfer text and files with other devices in the same LAN (without Internet) without any configuration other then installation, it's multiplatfom and easy to use. If you need to transfer data in a more advanced way I suggest SCP, based on the SSH protocol; it requires a more experienced user and some configuration (well documented online), but it's far more powerfull.