$replace is a Text Function.
The function returns the original text with all instances of the search text replaced by the replace text.
Original Text: The sentence or piece of data where the item that will be replaced is located. Accepts variables and functions such as $next list item, $list item, $random list item, $previous list item, and $table cell.
navigate("http://www.ubotstudio.com/playground/simple-form", "Wait") wait(3) type text(<about me textarea>, $replace("I like UBot Studio", "like", "love"), "Standard")
The original text being altered is the sentence "I like UBot Studio." Running the script replaces the search text "like" with the replace text, which is "Love". The resulting sentence is "I love UBot Studio".