I am using Lucas Chess but its opening lines don't display appropriately. Here the engine doesn't show opening lines automatically. What opening book can I use with engine for preparation of absolute opening? Or, are there any opening apps for practicing openings?
If you know what openings you want to play, you could input it into the free Lichess analysis board. This will allow you to see what the most optimal moves are and also see the common replies from top-level games. You can also continue playing from a given opening position against the engine for practice.
If you don't know what opening specifically you would like to play, I highly recommend this book to learn general opening skills.