Provided that the author of the page hasn't tried to limit the choices the person visiting the web page generally has three alternatives when it comes to where each link opens. Unless the browser has been configured to work differently simply clicking on the link with the left mouse button will open the new page in the current window. If you hold down the shift key while you click on the link with the left mouse button then most browsers default configuration will open the new page in a new window. If instead you hold down the CTRL key while clicking the link with the left mouse button the new page will open in a new tab in the existing window.
Not all browsers will necessarily interpret the shift and CTRL keys this way but most browsers do allow you to change the browser configuration so as to supply ways to distinguish between those alternatives.
The other alternative that will always work to give you a choice of where the linked page should open is to right click on the link instead of left clicking. This will open the context menu for the link and options for opening in a new tab or a new window will be shown there. The option to open in place of the current page may or may not be shown as some browsers assume that you'd have used the left mouse button if you wanted to do that. It is those browsers that do not offer this option that are the ones most impacted by web authors attempts to try to force you to open the next page where they want rather than where you want.
This article written by Stephen Chapman, Felgall Pty Ltd.