I can't find apple menu on my imac

It is an Apple icon at the far left of the menu bar

If you do not see it where Idrs indicates, yours screen may be zoomed in a little, makinghte virtual desktip larger tha your display.

You can try CONTROL-SCROLL to return the image to normal size, or do System Preferences > Accessibility > "Zoom" option (left pane) to see the keyboard shortcuts that control zooming in or out. YOU want to zoom out.