If you can't find the "extension=php_zip.dll" line in the "php.ini" file, you'll need to add it manually. Here are the steps:

Open the "php.ini" file located in the folder where PHP is installed (for example, "C:\PHP\php.ini") with a text editor.

Add the line "extension=php_zip.dll" at the end of the file, without the semicolon ";" at the beginning.

Save the "php.ini" file and close it.

Restart the web server or PHP service for the changes to take effect.

After adding the "extension=php_zip.dll" line to the "php.ini" file and restarting the web server or PHP service, you should be able to run the "composer require phpoffice/phpspreadsheet" command without any problems.