Retail sales have increased significantly in recent years, posing a major challenge for merchants in maintaining a consistent consumer experience across several channels. Changing consumer behaviors have had a big impact on this shift in buying patterns. Customers and retailers are also contending with the complications of adapting to these developments, which have been compounded by the global COVID-19 outbreak. The Internet retail sector, in particular, has seen significant development, which has surprised many. As a result of the digital revolution, online customers' preferences are changing, as they seek fulfillment amid a variety of available possibilities. The changing environment of customer behavior has been a key focus, formed in part by the distinct patterns that have emerged in reaction to COVID-19. This study seeks to shed light on how the retail phenomenon of COVID-19 has impacted customer purchasing behaviors, with the goal of discovering and validating unique insights that may affect decision-making, particularly among millennials in Sweden and China. In the beginning stages of this investigation, a comprehensive approach integrating qualitative and quantitative approaches was used to attain this goal. The study used a sequential exploratory design with two data gathering gathering periods. Our conclusions were guided by empirical data gathered through focus group meetings and replies to a web-based survey. Two key discoveries have given rise to a novel hypothesis, showing that customers in both Sweden and China enjoyed large benefits from online purchasing. Furthermore, the research has shown previously unknown and unanticipated ways in which COVID-19 continues to influence client purchasing behavior. This exploratory and constructive research seeks to enhance our understanding of these transitions, ultimately providing useful insights into the emerging retail scene in a post-pandemic world.