What should be the structure of my SOP if I’m targeting MS in the US? How much should I mention my work experience?
The structure of an SOP remains the same regardless of the country. The introductory paragraph should introduce you, your interests and perhaps what sparked an interest in the program you are applying for. It is not an autobiography, so keep it short and to the point. This does not mean you have to write bland sentences. You can be creative. In the next paragraph, summarize your graduate career - specializations, any projects you undertook, research papers, if any. Substantiate your claims with details like title of the project, name of the supervisor, what were your responsibilities, and what was the outcome of the project. You can also mention any internship experience you had and the areas you handled that will also help you with your graduate study.
Next, elaborate on your current endeavors - are you working? If yes, then what is your position, responsibilities? What have you learned? And how has this experience made you focus on graduate studies?
In the last paragraph, elaborate on your interests in the field you wish to pursue. What made you choose this program and university? Is there any professor whose research parallels yours? If so, mention it. You have to convince the admissions committee that you understand the scope of research in the field and are up-to-date with the current themes.
Hope this helps you!