To earn 15-20k per month online, you might consider:

Building and monetizing a niche website: Create a website around a specific topic and monetize it through advertising, affiliate marketing, sponsored content, and other methods.

Online course creation: Create and sell an online course teaching a skill or sharing your expertise.

Virtual event planning and coordination: Plan and execute virtual events for clients, such as webinars, conferences, and workshops.

Online coaching or consulting: Offer your skills as a coach or consultant in a specific area, such as business, personal development, or wellness.

Social media management: Manage the social media accounts for businesses and help them grow their online presence.

Web design and development: Offer web design and development services to businesses and individuals.

Mobile app development: Design and develop mobile apps for clients.

These are just a few examples of ways you can earn 15-20k per month on the internet. The key is to find a niche that you're passionate about and that has a strong demand, and then to consistently put in the time and effort to build and grow your online business.