Mailing List

I have a long mailing list of addresses (see attached). I wish to create a letter (template) which I'm going to send to each one of them --- the same letter. All I need to do is put a different address on each copy of the letter. I'm trying to determine the most cost-efficient method to merge all the name from the attached mailing list into my letter-template (or must they be individually typed, one by one? THEN, Part two, I need to address matching envelopes for each of them: I suppose I should just create labels with each of the names, and put the labels on the envelopes -- unless you have a faster, most cost-efficient idea.