How do I send data to the server from the client
Hi there Rajibhossan.
It's unfortunate that you didn't bother to specify the server type (web server, file server, etc.), the server's operating system (Windows, Linux, Mac, Unix. BSD, etc.) or the client's operating system. Knowing those information could greatly narrow down the suggestions that I could provide.
Anyways, this solution is likely to work in general if the problem is just transferring files from client to server.
On the server, you should set up an FTP server. For Linux, there's "vsftpd" that you can install through Linux software Manager or Synaptic or apt or yum. Basically, you just setup the server and give permission to the users that will accept incoming FTP connections. Here's a good guide on setting up a Linux FTP server: Linux For Windows, you can setup FileZilla FTP server.
Once you have FTP set up on your server, all you need for the client is to install an FTP client. FileZilla is an excellent graphical FTP application that works in Linux and Windows. Link FileZilla
Hope this helps.