Answer:
Main sequence star
Step-by-step explanation:
After stars are born they turn into what is called a protostar. This is when the true life of the star begins as it is the point in which all of its matter is coming together. After breaking through the protostar phase the star is fully developed and it begins fusing hydrogen into helium. This is when the star turns into a main sequence star. Stars remain in this phase for millions to billions of years, depending on the mass.
Fun fact - about 90% of the stars in the universe are actually main sequence stars, including our sun.