There are several different options for linking from one page to another. By demonstrating them it's possible to compare and contrast their benefits and drawbacks.
The preferred external document link type at UWA is "self" so as to stay within the same browser window and tab that the 'sending' link is in. For many CMSs this is the native link type created. This is good practice for all users and meets some high-level accessibility hopes.
Being consistent in your application of the chosen link type is extremely important because it eliminates unwanted surprises and confusion for accessibility users. The profusion of interfaces available allows users to customise link-opening as they wish, should the applied method not be to their liking.
How each link acts is largely the result of how a user’s browser settings are individually pre-determined.
Here is an arrangement of links as an example of how different link types are actioned by browsers.
After clicking through to a linked page, returning to your original page may be different, depending which option you moved away with. Options include using the 'Back' browser button, reopening the page or choosing the page/tab again.
The privately run W3 Schools site has some advice on link types including listed browser support of the mark-up.
Exceptions to opening links in the same tab are outlined in the W3C page 'Opening new windows and tabs from a link only when necessary'.
Touch screens can offer an 'open in new tab’ option if you touch and hold a link.