How can I send queue as LIFO?
The queue uses FIFO, as a queue. You could make a small change to the code to make LIFO if this is what you need.
Oh,How to change it?I am newbie to freertos.
I’d suggest you become a non-newie before trying to change that. Play around, trace, figure out how things work.
Good thing you are in the right place. freertos.org is a great place to learn how an RTOS works, and how perhaps to make a LIFO.
Of course after you read all the tutorials, maybe someone here would be helpful answering specific questions you might gain from reading.