The newsletter allows each company to maintain an intimate link between it and its customers or prospects. Indeed, subscribers to a company’s newsletter are generally customers or potentially customers and have agreed to receive promotional information and offers from the brand. Thanks to this channel, companies can make a good part of their turnover. It is indeed one of the most efficient acquisition channels today. It is therefore essential for a company not to neglect this point. However, not everyone is aware of the best practices for newsletter delivery. As a result, many people leave money on the table.