How and how to transfer backups over the Internet?

Question

Backup

DD!
There is a linux server. There are about a dozen branches with Windows machines around the city. Everything has internet access.
It is necessary once a day to automatically transfer a zip-archive (50-200 Mb) from each of the branches via the Internet to a Linux server.
So I don’t know how and what is the best way to do this?
Raise an FTP server and transfer files to it from Windows machines, or btsync, or rsync ...
Preferably not with simple software, but from cmd / powershell or something.
How "correct"? And don't forget about safety.

Answer 1

scp from openssh-client
Authorization can be configured by key.
The utility is a console one, so it will definitely start and work from cmd / powershell.

Answer 2

get-help start-bitstransfer (powershell cmdlet that works with resume) to the https (for security) server.
Bitstransfer does not know how to ftp\sftp
sftp in powershell - https://social.technet.microsoft.com/Forums/script
...
Or via cmd using winscp