Digital marketing and social media marketing are closely related but they are not the same thing. Here is the breakdown of these two:
The bigger umbrella: Digital marketing comprises all the online marketing tactics a business uses to reach a potential audience. There can be various tools, channels, and strategies in it. It generally includes the website, email marketing, SEO (Search Engine Optimization), pay-per-click ads, etc. along with social media marketing.
Tool within the bigger umbrella: Social media marketing is a subset of digital marketing that focuses on the correct utilization of social media platforms to reach consumers. Creation of content, community building, and running ads are some of the major strategies of social media marketing.