Hi
My phone is using USB Type-C connector.. but apparently Mavic only comes with iPhone Lightning and micro-USB cable.  
Can I connect my own USB Type-C cable to my phone, just like Phantom4 controller?  Does DJI has any plan to sell the USB type-C cable for Mavic controller?  Tks.

Yes there's a USB slot in the controller to connect your phone/tablet like in Phantom 4. DJI is selling the type c connector here: http://store.dji.com/product/mavic-rc-cable

have rc cable for usb type-c in the box of dji mavic ?

Yes you can use your own cable but the other end needs to be micro USB. If your standard charging USB cable had a 90° plug for the standard USB size then you possibly could use the bottom USB port on the RC if you phone will also fit into the cradle.
But better yet, just purchase the correct cable in the above post.

wouldn't it be better if you give us an option to choose which cable we want? not everyone uses an iphone to view the feed IMHO.

The cable is $8 but shipping is $10. Jeez!

My Mavic came with a USB Type-C cable!
Using it all the time with my HTC 10

Maybe it was just the early ones, but mine also came with a Type C cable (and a micro USB and Lightning too) - I had to order the one they didn't ship, a reverse microUSB.

I just got a Galaxy Note 8 with a USB Type-C connector, too. I have everything connected from my phone to the controller by going through the bottom USB of the controller using my phones charging cable.