Hello guys, i am new to this forum, I have read this term many times "Third Party".
What do u mean by this term "Third Party"? Could u tell me?

In the case of Third Party soiftware, this is an applicatio game or tool written by someone other than the handset manufactuer that you install yourself.

And, for completeness, the first party would be the device manufacturer, the second party would be the one who has (bought, owns) the device.