public float getDecimalRandomNumber(){
        // create instance of Random class
        Random rand = new Random();
        // Generate and return Random number with decimal
        return rand.nextFloat();
    }

driver.findelement(by.id("text box").sendkeys(""+getDecimalRandomNumber());

public class Sample{
        private static float inputNumber= 1.1f;

        public static float getInputNumber() {
            return inputNumber+ 0.1f;
        }
    }