You can send reinforcement troops to any of your clansmen. You can send them resource convoys as well. It can also be helpful to message your clansmen so that you know who is currently in need of economic or military aid. All of the activities listed above may be performed under the Membership tab of the Clan menu. Tap the "Action" button next to the name of the Commander you need and select one of the following actions:

Moving resource convoys between the bases of Commanders in the same Clan takes an hour at most, even if there is a great distance between them.