how to take a scrolling screenshot on mac

In Safari try File>Export as PDF…for a full webpage image.

Samrat10 wrote:

how to take a scrolling screenshot on mac?

https://eshop.macsales.com/blog/76508-take-a-screenshot-of-an-entire-webpage/

Some browser have this functionality: see Firefox - You can take screenshots to capture visible parts of web pages, or even full web pages, and copy or save these images

Take screenshots on Firefox - Mozilla Support

You mean a video recording? Or something else?

Command-Shift-5 is your friend, in any case. You choose what area of the screen to capture, you can capture video (with sound if you want to) or still images. And you can set a delay of 5 or 10 seconds before the shot is taken or recording starts, so you can capture exactly what you need.