Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Ods/Meta.php
public function write(Spreadsheet $spreadsheet = null)
    {
        if (!$spreadsheet) {
            $spreadsheet = $this->getParentWriter()->getSpreadsheet();
        }

        $objWriter = null;
        if ($this->getParentWriter()->getUseDiskCaching()) {
            $objWriter = new XMLWriter(XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
        } else {
            $objWriter = new XMLWriter(XMLWriter::STORAGE_MEMORY);
        }

        // XML header
        $objWriter->startDocument('1.0', 'UTF-8');

        // Meta
        $objWriter->startElement('office:document-meta');

        $objWriter->writeAttribute('xmlns:office', 'urn:oasis:names:tc:opendocument:xmlns:office:1.0');
        $objWriter->writeAttribute('xmlns:xlink', 'http://www.w3.org/1999/xlink');
        $objWriter->writeAttribute('xmlns:dc', 'http://purl.org/dc/elements/1.1/');
        $objWriter->writeAttribute('xmlns:meta', 'urn:oasis:names:tc:opendocument:xmlns:meta:1.0');
        $objWriter->writeAttribute('xmlns:ooo', 'http://openoffice.org/2004/office');
        $objWriter->writeAttribute('xmlns:grddl', 'http://www.w3.org/2003/g/data-view#');
        $objWriter->writeAttribute('office:version', '1.2');

        $objWriter->startElement('office:meta');

        $objWriter->writeElement('meta:initial-creator', $spreadsheet->getProperties()->getCreator());
        $objWriter->writeElement('dc:creator', $spreadsheet->getProperties()->getCreator());
        $objWriter->writeElement('meta:creation-date', date(DATE_W3C, $spreadsheet->getProperties()->getCreated()));
        $objWriter->writeElement('dc:date', date(DATE_W3C, $spreadsheet->getProperties()->getCreated()));
        $objWriter->writeElement('dc:title', $spreadsheet->getProperties()->getTitle());
        $objWriter->writeElement('dc:description', $spreadsheet->getProperties()->getDescription());
        $objWriter->writeElement('dc:subject', $spreadsheet->getProperties()->getSubject());
        $keywords = explode(' ', $spreadsheet->getProperties()->getKeywords());
        foreach ($keywords as $keyword) {
            $objWriter->writeElement('meta:keyword', $keyword);
        }

        //<meta:document-statistic meta:table-count="XXX" meta:cell-count="XXX" meta:object-count="XXX"/>
        $objWriter->startElement('meta:user-defined');
        $objWriter->writeAttribute('meta:name', 'Company');
        $objWriter->writeRaw($spreadsheet->getProperties()->getCompany());
        $objWriter->endElement();

        $objWriter->startElement('meta:user-defined');
        $objWriter->writeAttribute('meta:name', 'category');
        $objWriter->writeRaw($spreadsheet->getProperties()->getCategory());
        $objWriter->endElement();

        $objWriter->endElement();

        $objWriter->endElement();

        return $objWriter->getData();
    }
public function write(Spreadsheet $spreadsheet = null)
    {
        if (!$spreadsheet) {
            $spreadsheet = $this->getParentWriter()->getSpreadsheet();
        }

        $objWriter = null;
        if ($this->getParentWriter()->getUseDiskCaching()) {
            $objWriter = new XMLWriter(XMLWriter::STORAGE_DISK, $this->getParentWriter()->getDiskCachingDirectory());
        } else {
            $objWriter = new XMLWriter(XMLWriter::STORAGE_MEMORY);
        }

        // XML header
        $objWriter->startDocument('1.0', 'UTF-8');

        // Meta
        $objWriter->startElement('office:document-meta');

        $objWriter->writeAttribute('xmlns:office', 'urn:oasis:names:tc:opendocument:xmlns:office:1.0');
        $objWriter->writeAttribute('xmlns:xlink', 'http://www.w3.org/1999/xlink');
        $objWriter->writeAttribute('xmlns:dc', 'http://purl.org/dc/elements/1.1/');
        $objWriter->writeAttribute('xmlns:meta', 'urn:oasis:names:tc:opendocument:xmlns:meta:1.0');
        $objWriter->writeAttribute('xmlns:ooo', 'http://openoffice.org/2004/office');
        $objWriter->writeAttribute('xmlns:grddl', 'http://www.w3.org/2003/g/data-view#');
        $objWriter->writeAttribute('office:version', '1.2');

        $objWriter->startElement('office:meta');

        $objWriter->writeElement('meta:initial-creator', $spreadsheet->getProperties()->getCreator());
        $objWriter->writeElement('dc:creator', $spreadsheet->getProperties()->getCreator());
        $objWriter->writeElement('meta:creation-date', date(DATE_W3C, $spreadsheet->getProperties()->getCreated()));
        $objWriter->writeElement('dc:date', date(DATE_W3C, $spreadsheet->getProperties()->getCreated()));
        $objWriter->writeElement('dc:title', $spreadsheet->getProperties()->getTitle());
        $objWriter->writeElement('dc:description', $spreadsheet->getProperties()->getDescription());
        $objWriter->writeElement('dc:subject', $spreadsheet->getProperties()->getSubject());
        $keywords = explode(' ', $spreadsheet->getProperties()->getKeywords());
        foreach ($keywords as $keyword) {
            $objWriter->writeElement('meta:keyword', $keyword);
        }

        //<meta:document-statistic meta:table-count="XXX" meta:cell-count="XXX" meta:object-count="XXX"/>
        $objWriter->startElement('meta:user-defined');
        $objWriter->writeAttribute('meta:name', 'Company');
        $objWriter->writeRaw($spreadsheet->getProperties()->getCompany());
        $objWriter->endElement();

        $objWriter->startElement('meta:user-defined');
        $objWriter->writeAttribute('meta:name', 'category');
        $objWriter->writeRaw($spreadsheet->getProperties()->getCategory());
        $objWriter->endElement();

        $objWriter->endElement();

        $objWriter->endElement();

        return $objWriter->getData();
    }
Write meta.xml to XML format.

@param Spreadsheet $spreadsheet

@throws \PhpOffice\PhpSpreadsheet\Writer\Exception

@return string XML Output