Replace is used to replace an occurrence of a text string in another text string with something else. Your language may have options like only replacing the first occurrence or to do a global search and replace of all occurrences.
// in JavaScript
<script>
var s = "Automate Office Work";
var search = "Office Work";
var replacement = "Everything!";
var output = s.replace(search,replacement);
alert(output); // outputs "Automate Everything!"
</script>
// in PHP
<?
$s = "Automate Office Work";
$search = "Office Work";
$replacement = "Everything!";
$output = str_replace($search,$replacement,$s);
echo $output // outputs "Automate Everything!"
?>
// in Microsoft Power Automate's Expression panel
replace("Automate Office Work","Office Work","Everything!")
If you want to remove a certain string you could set your replacement string to be empty to effectively remove the search string.