Recieve data via uart/ Send Data with Lora ?

I am a beginner on stm32 microcontroller

Do you have experience with any other microcontroller(s) ?

Are you proficient in 'C' programming?

This is really not a beginner project!

Here are some beginner's Microcontroller Getting Started tips: 

http://www.avrfreaks.net/comment/1138166#comment-1138166

Here are some 'C' learning references & resources: 

http://blog.antronics.co.uk/2011/08/08/so-youre-thinking-of-starting-with-c/

I am wondering if there is any code examples may help me to understand how to recieve data via Uart (TX,RX) and send it via Lora Network

Not as such.

In general, do not expect complete, ready-made solutions.

What you will find is: 

1. Examples of using the UART;
2. Examples of using LoRa.

It's up to you to bring the two together...