Many overseas moves are in sea containers, either 20' or 40'. As such the load will travel well, and never be touched until it's unpacked at the other end, except possibly for customs exam.

The folks who do this tend to know what they're doing, and will probably pad the bikes and place then along a wall trapped by some boxes or furniture. You shouldn't box the bikes because that it impossible to determine the condition.

But there are things you can do. Shift to low so both derailleurs are inboard, pad them and the tubes with bubble. Remove both pedals so they have a flat profile, maybe also turning the handlebar. Also cover the saddle, and if you've turned the bars, double pad between them and the frame.

In the end, you want the bikes to be visible so the mover can be sure they're OK. If you're a fast worker, you can let them check the bikes, then prep them while they work on other stuff.

OR

Simply remove the pedals, shift to low, maybe turn the bars so the bikes are flat, and let the movers place them with those large blankets they use everywhere.