Decide the purpose of the time capsule; is it to remind yourself of how you once were? If the time capsule is for your organization, what would employees or students be interested to hear about in the future? The answers to these questions will dictate not only what items you include in the time capsule, but also what you include in your letter.
Begin the letter by typing the date; the date is the most important aspect of the time capsule. Type "Dear (recipient of the time capsule)" followed by a colon.
Explain the purpose of the time capsule. If it is for an organization, remember that the letter will probably be read at some sort of public ceremony, so write as if you are speaking to a large crowd. Tell the crowd why you decided to create a time capsule. If you are writing to yourself, keep in mind that the future you is a different person. Tell yourself what you hoped to accomplish by writing the letter and creating the time capsule.
Explain the items in the capsule. Describe what each item is and its significance. If the capsule is meant to be opened far in the future, the recipients of the letter might not know what the items are.
Provide any other information about yourself or your organization that you feel might be interesting. For example, if the time capsule is meant for yourself, it would be revealing to speculate about what the future you will be doing. If the capsule is meant for your business or organization, give a snapshot of what business is like now and speculate about what your business will be doing in the future.
Sign the letter, or, in the case of an organization, have everyone sign it.