To ensure the best readability, use large, bold, sans-serif fonts. A thirty-two point sized bold font is a good standard for general text. Do not use less than a font size of 26 points. Fonts larger than forty points can incorporate serifs, and are good for titles. Here are some good examples of standard sans-serif fonts:
Feel free to experiment with other sans-serif fonts, and make time to test your choices. Remember that internet video conferencing will degrade what you thought was readable.
With text, always err on the side of large.