Many of my readers have started proofreading from their iPads, scanning legal documents for court reporters as a result of the Proofread Anywhere eCourse I recommend. You can read some of their testimonials in the comments on this post. They offer a 7-day intro course free so you can decide if that line of work is right for you before you pursue the training.
After your initial training the real work begins. The best virtual assistants will scour popular sites such as Upwork and Freelancer, looking for work from home job opportunities and new job leads. Also, be sure to completely fill out your profile and list all pertinent skills. Potential clients can search for qualified remote workers and proactively contact them about potential job opportunities.