I am developing a game using libgdx framework. How can i achieve scene2d action on bitmap font object ? so that i can write some text like score,message and run action like scen
Take a look at the Label class, particularly the constructor that takes a CharSequence and a LabelStyle. When you initialize your LabelStyle you can supply a BitmapFont.
Please note, if you'd like to scale or rotate the label you'll need to wrap it in a Container or add it to Table with setTransform() enabled. (This flushes the SpriteBatch so use it wisely.)