I feel that the answers my friends have given do not really answer your question.
Your question is about the new Moon and why is it always new?
My question is, is it new? When you see the Moon, with the Sun shining on it look at it’s features. Record in some way what you see. Make a drawing, take a photo. Look at it the following night and see whether more features have been added. Record them. Observation and recording are important features of science investigations. You have a fabulous question which you can answer.
Unsure than ask a question.
Do the above and then read the below.
The Moon is a difficult object to follow. One month it appears every night in the night sky and the next month … no sign of it. Now and again you might see it in the sky during the day! it is a very, very confusing ‘animal’. This is because it orbits the Earth every 28 days so for some time each month those who live in the southern part of our planet can see the moon while in those in the northern part see it in the other part of the month.