Serving legal documents is very similar to letter-type documents, except that the recipient unit is changed to the delivery unit, which is written at the end of the document and is introduced with "hereby"; but the recipient unit must be written first. Lawyer practice documents are mostly used to serve documents. For example, documents must be served for various complaints. Part of the service document requires that the basic information of the parties be stated in the first part of the document. This form is also used when writing on behalf of a lawyer or when a client writes an application on his or her own behalf. Square brackets are used to treat the value in the brackets as an address. Parentheses are used to offset, i.e. the value inside the parentheses should be added to the value outside the parentheses.