The first step is to download a photo of a moon from free stock photo websites like Pexels, Pixabay and Unsplash. Shutterstock, Adobe Stocks and Dreamstime works as well but you have to pay a premium for it. Pick one option and get started! Now that you have your moon stock photo, draw out a circle using the Ellipse tool (U) on your image to place it. Next, place the moon on a layer above the circle you previously drew. The following step is to select your moon layer and right click to choose “create clipping mask”. The background will disappear, leaving you with only the moon.
Now it is time to make your moon glow! Double click on the circle layer to tweak the settings (opacity, noise, spread and size). Play around and see what works for you. It is all trial and error. Do not be afraid to make mistakes. Once you are satisfied with the glow, select the Lasso tool (L) to crop and mask out the parts you need. The final step is simply doing some touch ups here and there to make your moon blend in with your image. Add some minor noise and soft blurs then you are good to go!