Currently, there are many digital marketing platforms to promote and sell, and WhatsApp Business is one of them, since it has been revolutionizing electronic commerce and has allowed companies to digitize in pandemic times, being a fast, easy, and safe way. This study aimed to diagnose the use and management of WhatsApp Business in fast food restaurants, and to determine how beneficial it had been as a marketing strategy during COVID-19. The methodology used to determine was a mixed nature, which implied the collection and analysis of data in a qualitative and quantitative way, considering an instrument (questionnaire) as a basis; In addition, the direct observation method was used, for which a checklist was prepared. The results showed that 63% of the companies that used WhatsApp Business as a marketing strategy stated that the tool was particularly useful to enhance their brand as companies and their sales during this critical period. On the other hand, it is indicated that WhatsApp Business worked in an adequate and functional way in most of the companies. The COVID-19 pandemic and the lockdown measures accelerated the digitization process of many companies, since most of them relied on digital marketing tools such as WhatsApp Business, which generated benefits during this time, and it was reflected in the portfolio of clients who contacted daily in a profitable medium.