The light-scattering qualities of our atmosphere disperse sunlight throughout the sky, so stars aren't visible during the day.
With the help of small particles in the atmosphere in the way of the light, it can scatter a lot.
This phenomenon is known as the Scattering of light.
Because the earth's distance from the sun is shorter throughout the day, the dispersed light is so intense that the other stars are not visible during the day.
Hence, The presence of bright sunlight makes the stars invisible during the daytime.