Freelancing: Offer your skills on platforms like Upwork or Fiverr. You can offer services in various fields such as writing, graphic design, programming, or marketing.
Online Courses: Create and sell courses on platforms like Udemy or Teachable. Teach others your expertise in a specific subject and earn money from course sales.
Affiliate Marketing: Promote products and earn a commission for every sale. Join affiliate programs like Amazon Associates or ClickBank and promote products through your website, blog, or social media.
E-commerce: Start an online store using platforms like Shopify or Amazon. Sell physical products or dropship products from suppliers.
Digital Products: Create and sell digital products like ebooks or design assets. Platforms like E-junkie or Creative Market allow you to sell your digital products to a wide audience.
Remote Consulting: Offer your expertise through virtual consultations. Use platforms like Zoom or Skype to provide services such as business consulting, career coaching, or financial advice.
Blogging/Vlogging: Monetize content through ads, sponsorships, or affiliate marketing. Start a blog using platforms like WordPress or create a YouTube channel. Build an audience and earn money through advertising and partnerships.
Stock Photography: Sell your photos to stock photo websites. Platforms like Shutterstock or iStock allow you to upload and sell your high-quality photos to individuals and businesses.
Virtual Assistance: Provide administrative support to businesses remotely. Offer services like email management, social media scheduling, or customer support. Websites like Upwork or Freelancer connect virtual assistants with clients.
Cryptocurrency Trading: Invest and trade in cryptocurrencies. Platforms like Coinbase or Binance allow you to buy, sell, and trade various cryptocurrencies such as Bitcoin, Ethereum, or Litecoin.
These are just a few examples of how you can make money online in the 21st century. Each method requires different skills and strategies, so explore the options and find what suits you best.

Please note that the provided links are for reference purposes and may change over time.