What are the applications for synchronizing / backing up folders in Win?

Question

Data synchronization

Recently I bought an ssd in a laptop, and to put it mildly, there is not enough space, as a result of which the idea arose of setting up synchronization with an external HDD, but I could not find suitable software.
There are folders on the SSD: Video, Programs, Photos, Music, Android, Desktop
and exactly the same set of folders on the external HDD.
I am interested in a program that, when launched, will scan folders, compare their contents and, in the absence of any files on the HDD, copy them from the SSD (unilaterally).

Answer 1

freefilesync.sourceforge.net for Windows, Linux, MacOS.
If the questioner's OS is secret, then FreeFileSync would be the most likely answer.

Answer 2

Good afternoon!
What operating system is on the laptop?

Answer 3

So there is a "synchronization center" in the system itself. I have been using it successfully for two years now.
I set it up for a long time, I won’t tell you the procedure. But Google easily leads to manuals. For example here: synchronization center

Answer 4

I kind of wrote in the title win) I will clarify win 8.1