Without knowing the child’s age, it is difficult to form an answer. Is the child old enough to be in social settings with other children who may talk about her father being in jail? If she is, then it is very important that she know this information AND she knows how to respond to others should they tease her about it.
Again, based on her age, she should be told that her father has continued to make poor decisions and will pay for law-breaking behavior by going to jail until she is in ______ grade. He will not be able to attend sporting events or school programs. However, Grandma and Grandpa will be there for her, and you will always let her father know that these activities are happening and how they turned out.
When she is old enough to write letters, help her with that. At meals and before bedtime, encourage her to pray for her father so he can learn how to make better choices so he can be with her. Drawing and coloring pictures for him is another way to stay connected during his incarceration. If he sends letters and pictures to her, screen them for appropriateness.
We would not recommend taking her to jail to visit him. Keeping her life at home as consistent and predictable as possible will help her feel safe, which is important to all children.