Follow up letter serves as reminder or summative description of some proposal. The content of the letter can vary according to the need. It is generally informative. The follow-up letter should include a brief but clear description of all the significant issues of the previous documents following which it has been framed.
The letter should be written in precise and professional manner. The content in follow up letter should be similar to the actual letter sent before.
The letter can be address to individual, to authorize person or department and they should be aware of the preceding document and its content.
The letter can be brief but needs to be clear and understanding language.
Generally follow-up letters are given to gather information and latest updates of the concerned matter, and hence the purpose should be stated very clearly for easier understand ability and faster processing.