Transfer my own data from FC to GS via UART and MavLink

Hi everybody. I need to transfer some data from uart of my Arduino to uart of flight controller. And then to transfer this data to ground station. Anybody can me tell if it is feasible to do this? And, if yes, where can I find an information about it?
Thank you all in advance for any help!
With my regards, Oleksandr

There are a lot of threads in this forum explaining how to do that. Just search a bit.

Thanks, my friend! But I will be very appreciative if you help to find this thread. I tried to do it, but I can`t find it…