You First Need to Learn the color theories and website design anatomy. For that first learn to use softwares like Sketch(if IOS), Figma Or Adobe XD.
If you master those softwares then, you can automatically create web designs for commercial projects.
For Prototyping, You have to undergo Some Courses on Adobe XD in udemy, or some other sources, it's truely based on your choice.
For Crash Course on Adobe XD -- > My Suggestion.. Adobe Xd on LevelUpTutorials.
After Some Prototyping, Learn to do some custom animations. (With Or Without Plugins)
Get inspirations From Behance,awwwards,Dribble....
This is the starter Pack For UI/UX Designer.
After this, You Can Jump Over to Shift Nudge.. The Course Currently Trending Right Now!.