It's called "green screen " you must do the recording in front of the green screen (other colors work but green is preferred by most software)
Then using the software you replace the green with your chosen background.
I have Wondershare Filmora, but it is complex and buggy and their support is in China.
There are many other apps that will do this... good luck
Thanks @jerrytsuseer
By the way, may I know how did you get that background on your video ?
I'd like to do that for my next video.
It's called "green screen " you must do the recording in front of the green screen (other colors work but green is preferred by most software)
Then using the software you replace the green with your chosen background.
I have Wondershare Filmora, but it is complex and buggy and their support is in China.
There are many other apps that will do this... good luck