Taskbar moved to the bottom of the screen on my MacBook Air

You can move the Mac dock by double clicking or control-click the task bar and choose the desired side from the position on Screen menu.

Using the Dock on Mac ⇢ Use the Dock on Mac - Apple Support

dfplumber wrote:

My task bar moved to the bottom of the screen//???? how to move it bask.

Can you explain what you mean by "task bar?" That's not a term Apple uses. Where was it before?

I think the author is referring to the Mac Dock.