Google proposed making HTML 5 the default over Flash in its Chrome browser back in May. Chrome 55 has been released and now defaults to HTML5. The exception is when a site is Flash-only or if its one of the top 10 sites on the web. For every other website you visit, you'll be asked to enable Flash the first time you go there.
When uploading content to a Mindflash course, Arranger, this part of the Mindflash platform uses Flash. The link below provides steps to enable Flash.
Enable Flash in Chrome: Enable Flash
For all other web browsers, the following link provides the details.