If you have a friend or family member in prison--or if you decide to become a pen pal to an inmate you have never met before--you will have to learn some rules and regulations to send the person mail regularly. Each detention centre, whether state or federal, will have different policies regarding the kind of stationery to use, content you can include and the language you can write.
Follow all guidelines about the types of paper or pen ink to use. At some detention centres, you cannot use any colour of pen ink except for blue or black. You also may be restricted to just using lined notebook paper or white copy paper. There may be rules that don't allow you to type your letters, instead asking that you only hand write items to inmates. Find out what kinds of restrictions are placed on the letters inmates receive at the detention centre your loved one is in.
Watch your language. The authorities at the detention centre will be reading your letters before an inmate sees them, and they will censor your language if they think it is necessary. While you may be able to get away with some "adult" language and content, your letter may be thrown away if it is deemed too pornographic or inappropriate for an inmate to read.
Censor yourself for content, as the authorities will do it if you don't. Do not write a lot about how horrible the prison system is. Avoid saying controversial things about any government or policing agency. It is also not a good idea to include any information about a case or a charge against someone. Anything you say can be used against the inmate.
Mark the prisoner's classification number on any mail you send. Even if you send a letter every day of the week, without the classification number for the inmate you are sending it to, it might not get to the person it is supposed to reach. Most detention centres have hundreds or even thousands of inmates, and they are not usually known by their first or last names.
Do not include any articles, stories or pictures that could be considered insubordinate. Stories about prison riots, poor treatment in detention centres and lack of rights given to inmates will not be passed on to the prisoner. They may be thrown away immediately, and the authorities may not allow you to send mail to the inmate any longer.
Try to keep your letters positive so that they brighten the day of the inmate.
Don't write about things that you know will upset the prisoner.