A digital marketer handles a variety of tasks in online marketing – managing online advertising and search engine optimization (SEO), implementing tracking systems (e.g. to identify how a person came to a retailer), web development, preparing creatives, implementing tests, and, of course, analytics. There are typically three types of employers:
Marketing agencies that contract out their services
Digital platforms like Salesforce, Amazon, Shopify, Facebook, etc.
If you are new to marketing, but familiar with statistics and analytics, an agency offers a good way to get started, as you are surrounded by people who know the business in its many aspects and manifestations (as opposed to a job where you are more of a sole practitioner). It can also be useful to get certifications in the mechanics of Google Analytics, DoubleClick Campaigns, Adobe Analytics, etc. For example, Google has free online courses and certification in its Academy for Ads.