Where is refresh button on an apple computer the I-Mac computer to be exact?

On an iMac, the refresh button is not a dedicated key but can be easily accessed through the web browser. In most browsers like Safari or Chrome, you can refresh the page by clicking the circular arrow icon located in the address bar or by pressing the keyboard shortcut Command (⌘) + R. Alternatively, you can right-click on the page and select "Reload" from the context menu.