In the era of big data and digital transformation, Master Data Management (MDM) is pivotal in helping businesses extract maximum value from their data. Data onboarding, a crucial aspect of MDM, involves integrating offline or external data into a digital format, matching it to online identifiers, and using it for purposes like Entity Resolution, advertising, marketing, and analytics. This process enables businesses to centralize data, clean it, transform it, and merge it to create a single, accurate view of their customers, ultimately enhancing their marketing strategies with better ad targeting, personalized emails, and more. Integrating offline and online data offers a more holistic view of customer behavior, improving advertising targeting and optimizing customer experiences. By doing so, businesses can benefit from improved data quality, increased efficiency for marketing teams, better understanding and visibility for sales teams, and more informed decision-making for leadership teams. The process typically involves multiple steps such as data collection, identity resolution, data transformation, and data activation, with security and compliance being paramount to ensure the integrity and trustworthiness of the data utilized by organizations.