Standard font #12, Tahoma is also good, same size. Be sure to have documentation of all you are claiming, and pictures of the house - before, during and after they move out. Send the papers return receipt/certified mail. File an eviction notice with the court and have them served by authorities.

As a general rule. Something simple. Arial for type font. 10pts. is probably best.(no less than 8, no higher than 12)

Keep the letter short, formal, and professional… do yourself a favor and at least look online for some sort of template, or example of an eviction or “pay up or else” letter. As you may have certain restrictions by law on what, how, or why you can send such a letter.

Stick to the facts.

ie… you agreed to pay such and such rent, you are such and such time past due, you owe such and such amount. please contact us to resolve this issue. Failure to resolve this issue will result in additional action taken to recoup this amount.

blah blah blah.

try not to use any direct threats, or even veiled threats,

also, keep a copy of the letter for yourself. And spend the extra dollar or so, and go to the post office and send it certified mail, so you have proof they received it.

may also be a good idea to contact a lawyer, or see if you can’t contact your state’s dept for …i dunno. land lords or whatever housing dept the state may have for delinquent renters.

Rather than trying to create your own, why not use one of these free templates?