Exactly what you put in your letter will depend on what the two parties are agreeing on, but the key is to include absolutely everything.
Start with the obvious
This should be the date that the agreement was drafted, the dates that it applies to and the date that the agreement comes into effect. You will also need to put the full names of the two parties as well as their addresses so that the identification of the two parties cannot be questioned.
Don't use nicknames
An agreement between Dave and Pete is meaningless in law. Put full names even if the people in question are only ever called by a shortened version or a nickname. In other words, write down the names as they appear on their birth certificates. If a person goes by a different name for business purposes, still write their full name on the letter but also include an AKA (also known as).
Spell out the terms of the agreement
This means every last point must be written down. If it is an agreement about one person lending another some money for example, the agreement should state the amount being lent, the interest that will be charged, the rate that the money will be paid back, the dates of the payments, the amount of each payment that is expected and any penalties for failing to make payments. A good idea would be to refer to any agreement that you already have from your bank, etc and copy it, substituting your own information.
Allow space for both parties to sign
In order to make the document a legal agreement, it must be signed by both parties. Leave a space for signatures and ask each party to sign their name, print it underneath and also date it. Depending on how serious the agreement is, you could also ask for the signatures to be witnessed. Then the witness would need somewhere on the document to sign and write his name, as well as the date.
Start with the obvious
This should be the date that the agreement was drafted, the dates that it applies to and the date that the agreement comes into effect. You will also need to put the full names of the two parties as well as their addresses so that the identification of the two parties cannot be questioned.
Don't use nicknames
An agreement between Dave and Pete is meaningless in law. Put full names even if the people in question are only ever called by a shortened version or a nickname. In other words, write down the names as they appear on their birth certificates. If a person goes by a different name for business purposes, still write their full name on the letter but also include an AKA (also known as).
Spell out the terms of the agreement
This means every last point must be written down. If it is an agreement about one person lending another some money for example, the agreement should state the amount being lent, the interest that will be charged, the rate that the money will be paid back, the dates of the payments, the amount of each payment that is expected and any penalties for failing to make payments. A good idea would be to refer to any agreement that you already have from your bank, etc and copy it, substituting your own information.
Allow space for both parties to sign
In order to make the document a legal agreement, it must be signed by both parties. Leave a space for signatures and ask each party to sign their name, print it underneath and also date it. Depending on how serious the agreement is, you could also ask for the signatures to be witnessed. Then the witness would need somewhere on the document to sign and write his name, as well as the date.