This video will show you how to set up an FTP server on Windows 10 to transfer files on your local network. This can be extended to work over the internet, but you will need to set up port forwarding and dynamic DNS.
The software you need is Filezilla server from https://filezilla-project.org/
When it installs, you can leave everything as default, the only one you might want to change is if it starts with Windows or not.
Once installed, just click on the icon at the top that looks like a single face. Here you can create a user on the right, by hitting add. Give the user a name, and leave the group empty. Then hit ok.
Once the user is added, you can choose to add a password by clicking the check box in the middle for password, then typing in a password.
Then go to the shared folders tab on the left. Here hit add to add a folder to the FTP share, the first one will be your home folder. Choose whatever folder you want to share from the browse window.
After selecting the folder, choose the permissions you want for that user. By default they only have read file, but if you want them to be able to add new files check write on the right.
Now you just need to use your IP address on any other computer on the network to connect.
FInd you IP address by searching cmd and going to the command prompt, and typing ipconfig. Then you should see your IP address listed as IPV4 address.
Go to any other computers file window (or browser) and type in ftp://YOURIPADDRESS
This will prompt for the username and password you created. Once entered, you can use the folder (depending on permissions) as if it was a folder on your local computer to share files over the network.