Hi Islam,
To do drone mapping with Reach, you need to work in PPK. Reach M+ or Reach M2 is needed to be connected to a camera’s hot shoe to register precise time marks for each photo. To obtain precise coordinates for these time marks, you need to post-process raw data logs from base and rover.
However, the DJI Mavic Pro drone’s camera doesn’t provide hot shoe access, so it can’t be easily integrated with Reach.
If you want to improve the accuracy of your survey with DJI drones, you can place GCPs in RTK mode. You can learn more about the RTK mode here. To collect points, you can use our ReachView 3 app. Also, this topic on our community forum might be interesting for you.