In SMS marketing, a keyword is a unique term (it can include letters as well as numbers) that people text to your short code to join your list. For the best results, you want to choose a keyword that your customers can easily remember. You also want to select something that’s relevant to your brand. On top of your keyword opt-in strategy, it’s a great idea to have a sign-up form somewhere on your website where visitors can enter their details and subscribe directly to your SMS marketing. To prevent fake DLR in your SMS campaigns, use an SMS testing service like Testelium https://testelium.com/features/ .