The_author() function in WordPress is used to display the name of the author of the a post. When you call the_author() within the WordPress Loop, it will output the display name of the post's author. It doesn't return a value; it directly prints the author's name.
The the_author_link() function in WordPress is used to display the author's name as a hyperlink. The hyperlink typically points to the author's archive page, which lists all posts written by that author. When you call `the_author_link()` within the WordPress Loop, it outputs the author's name as a clickable link.
Some of the Similarities are that both functions are used to display information about the author of the current post, secondly both should be used within the WordPress Loop to correctly identify and display the author of the current post, lastly both functions rely on the context of the current post to fetch the author's information. Differences are in the_author() it outputs the author name display as plain text, however in the-author_link() outputs the author name as clickable hyperlink.
In summary the_author() Displays the author's display name as plain text, and is used within the WordPress Loop to show the author of the current post. The_author_link() Displays the author's display name as a clickable hyperlink, and used within the WordPress Loop to link to the author's archive page.