I've been digging around to find a proxy application something like `proxifier` in windows but cannot find any thing! and then tried to configure the system wide proxy setting in network section of Ubuntu’s system setting and I configure the proxy setting but it seems it does not apply anything...

here is my questions : 

Is there any proxy application to use like `proxifier` in windows!?

If there is no proxy application how can I configure system's proxy setting manually!?

thanks in advance