To earn $20 online per day, consider freelancing on platforms like Upwork or Fiverr, taking paid online surveys, participating in affiliate marketing, or doing micro-tasks on platforms like Amazon Mechanical Turk. Additionally, explore gig economy apps, sell items on platforms such as eBay or Poshmark, or offer virtual assistance services. Engaging in online tutoring, content creation, or remote part-time jobs are also viable options. Combining these methods can help you reach the $20 daily target.