Final answer:
The Remington No. 2 typewriter added upper and lower case letters in 1878, enhancing its functionality and usability.
Step-by-step explanation:
The familiar lower and upper case was added to the Remington No. 2 typewriter in 1878 by introducing a new design.
Prior to this, the typewriter only had uppercase letters. The addition of lower case letters made it easier to write and compose documents more efficiently, as it allowed for greater flexibility in formatting texts. With both upper and lower case letters, typists could now create documents with proper sentence structure, punctuation, and emphasis on words or phrases.
This innovation greatly improved the usability and popularity of the typewriter, as it made it more practical and functional for various writing purposes.