You can find the DJI GO 4 APP and the DJI FLY APP from the DJI webpage here:
For DJI Mini, 2 and 3 PRO, Mavic Air, Air 2, Air 2S and Mavic 3
DJI FLY APP https://www.dji.com/downloads/djiapp/dji-fly
DJI GO 4 https://www.dji.com/downloads/djiapp/dji-go-4
You can also download the apps from the TRIPLTEK server here:
Click here to DOWNLOAD the DJI APPs