How to write files to the server?

Question

PHP

Hello, I have a program (I write in C #) that is used by 100-200 people a day, it reached 700. The program has a binding that is implemented on the server (the program sends a request if the binding is valid = everything is OK, otherwise the program closes.)
The program also has logging which is saved in a .txt file and is located on the user's computer.
QUESTION: What is the best way to copy the log file to the server?
I thought: the file is saved on the user's computer -> sent to the server via FTP (but something is alarming, I think it will be too much load on the server, because so many files will be uploaded to FTP - it will be bad)
What other options are there for copying a file or text which is in the file on the server?

Answer 1

Maybe it's better to use REST instead of sending files?

Answer 2

If you just copy the files, then just do it separately.
At least write the program yourself (as a service) or some other tool.
Set that you need to copy at night, all the logs for the previous day.