The process of making white wine compared to red wine is not about the color of the grapes. Many people think that white wine is made from green grapes and red wine is made from red grapes. But that's not actually the case!
In fact, white wine can be made from any color of grape. The difference is in whether or not the skins are used: for making white wine, winemakers will remove the grape skins and only use the colorless inside flesh of the fruit.
The infographic below from Wine Folly gives a great overview of the white wine making process: