There are many ways you can achieve this as below. 1. Process Builder 1. System Administrators can do it easily 2. Irrespective of Master Detail or Lookup, should work 2. Apex Trigger 1. This is helpful if you have advanced processing logic that is needed. 2. If you go with this option, remember to make a custom setting to that you can use it to turn a trigger on or off without deactivating it through a code deployment. 3. Cross Object Formula 1. If you have a reference to the child account on the parent account, you can use a formula (checkbox) to do this. 2. Provided your object relationship is Master Detail all the way in the hierarchy