You can do this in Photoshop. Right Click on the Image in Lightroom >> Click on Edit in Photoshop.
This will open the image in Photoshop and you can make all the required changes and click on save under File menu and it will bring the image back to Lightroom with the edits.
In Photoshop you can start with shape tools to create a shape, then use the fill option to fill it with the color. finally you can use the text layer and write the text.