can u tell me how an ad is designed before it goes to the print in newspapers?

[PRACHI]

You should know about some designing software like Photoshop and Corel Draw. Since you are designing ad for print so you have to use Corel Draw because it works on CMYK, which is appropriate for print ads while for digital ads Photoshop is preferred as it works on RGB color format.
Also you have to look for colors you are using as designing has some principles like you have to use only 2-3 colors in an ad and use visual on the right side.