The “correct” percentage to bluff in poker is not set in stone and can greatly vary depending on a number of factors, such as your position at the table, the types of players you are up against, the current state of the game, and your table image (i.e., how the other players perceive you).
That being said, some poker theorists suggest that a good starting point could be to have a balanced range, where you bluff approximately one third of the time that you are betting for value. This means that if you’re betting with strong hands 70% of the time, you might want to bluff about 30% of the time.