Solution 34834: Typing Text Labels on Graph Screens on the TI-83 Plus and TI-84 Plus Family of Graphing Calculators.
How do I type text labels on graph screens on the TI-83 Plus and TI-84 Plus family of graphing calculators?
The text() function can be used to create labels for graphs. The text() function writes text on graphs beginning at pixel (row, column), where 0£ row £57 and 0£ column £94. The function is located in the DRAW menu which can be accessed by pressing [2ND] [PRGM]. The syntax for the text() function is:
text(row, column, text1, text2,…)
Please refer to the example provided below:
1) Press [2nd] [Mode] then [Clear] to go to and clear the home screen.
2) Next press [2nd] [DRAW]   [,]  [,] [ALPHA] ["] [X,T,θ,n] [ALPHA] ["] [)] [ENTER].
This will display the text label X at point (5,5) on the graph screen.
Please see the TI-83 Plus and TI-84 Plus Family guidebooks for additional information.