Since Chrome version 76, all Flash content is blocked by default. When Flash is blocked, click the blocked plugin icon in Chrome's address bar and click Manage. This takes you to the Flash settings page, which you can also access from Settings » Advanced » Privacy & Security » Site Settings » Flash.
Click the toggle here to set Chrome to Ask first.
Now, when you visit a website with Flash, you can click a Flash object on the web page and click Allow to view it.