How to block program in firewall in Windows?

You can use below steps to block a program using Firewall:

• Open the Run window (Windows key + R).
• Type "WF.msc". This should open up Windows Defender Firewall with Advanced Security.
• Click on "Outbound Rules" in the left sidebar pane.
• Select "New Rule" in the right sidebar pane.
• Check if "Program" selected, click on "Next".
  
   
• Browse and locate your program executable. (.exe file), which you want to block.
• Select Block the connection.
• Click Next.
• Let the checkboxes remain as is if you want to block the connection everywhere regardless of the network it is connected to.
• Click Next.
• Write an appropriate Name and Description so you know which program is being blocked by the rule. (Will help you in understanding, when you need to unblock it in future.)
• Click on Finish.

If Future if you wish to unblock the program connection, simply select and right-click on it, and select "Delete", once you will delete the rule, program will be unblocked.