Have seen an example in sample Editing Tools. if you see the sample link, the text is editable and a color popup appears on click of text.
trying to replicate the same feature in the 4.15 version, but no luck.
You will need to use a TextSymbol:
1. Have a button that users can click to add text with a listener
2. When the user clicks the button the listener calls a function that prompts the user to click on the map
3. Capture the map click coordinates
4. Prompt the user for the text they wish to write, using a dialog box
5. Add a point graphic to the map using TextSymbol for its symbology