The rapid growth of social media has transformed traditional marketing and reshaped global e-commerce practices. This study examines the major platforms used in social media marketing and analyzes the impact of social commerce and influencer marketing on worldwide e-commerce sales. Social commerce enables direct purchasing through social media platforms, while influencer marketing enhances consumer trust, engagement, and purchase intention through authentic and relatable content. The study further explores key challenges faced by brands, including issues related to influencer authenticity, accurate measurement of marketing performance, and compliance with evolving regulatory and disclosure requirements. Findings from existing literature indicate that although social commerce and influencer marketing significantly boost brand visibility and online sales, their effectiveness depends on transparency, credibility, and ethical practices. The study contributes to a better understanding of how businesses can strategically leverage social media marketing while addressing emerging challenges in the digital commerce ecosystem.