After a divorce, one parent might move away from their children. This isn't an easy situation for anyone involved, but trying to find ways to help the children grow their relationship with both parents has to be the main priority. There are several ways that this positive long-distance parenting can happen, but they rely on the adults working together.
One thing that must be established early in the situation is making sure that the children have free communication with the parent they aren't with at that time. This should be uncensored, so the parent who does have the children shouldn't try to control or steer the conversations.
Determining the methods of communication that are appropriate is important. There are so many options now. Children can call their parent on the phone, but there are other choices that might also work. Text messaging might work for children who can read and type. Video chats can work for children of all ages and can help immensely since the child will be able to see their parent.
Both parents should find ways to keep the nonpresent parent included in the child's activities. This might mean using video chats to go over homework assignments or read bedtime stories. Sharing footage of special events like school plays can also help.
It is a good idea to have the terms of communication and other similar matters covered in the parenting plan. This gives both parents an outline of what is expected in the situation. Conflict resolution and information about consequences for failing to abide by the agreement should be included.