You just enclose the money order to the address where you send mail to the inmate. On the money-order, there will be a place to put his number and it will be deposited there where he or she is incarcerated and can be used to buy personal things, such as deodorant, coffee, etc. Somewhere in the letter, tell the inmate you are enclosing a money order in the amount of ?, so he or she will know it should be included within the letter