Spreadsheets, driven by code.

<?php

require 'vendor/autoload.php';

use \PhpOffice\PhpSpreadsheet\IOFactory;

$inputFile = 'workbook.xlsx';

$reader = IOFactory::createReaderForFile($inputFile);

// The names alone. This does not load a single cell.
$names = $reader->listWorksheetNames($inputFile);

echo "Sheets in {$inputFile}:\n";
foreach ($names as $i => $name) {
    echo "  [{$i}] {$name}\n";
}

// One entry per sheet, with its dimensions - still without loading the cells.
echo "\nSize of each sheet:\n";
foreach ($reader->listWorksheetInfo($inputFile) as $info) {
    printf(
        "  %-10s %5d rows x %2d cols (last cell %s%d)\n",
        $info['worksheetName'],
        $info['totalRows'],
        $info['totalColumns'],
        $info['lastColumnLetter'],
        $info['totalRows']
    );
}

// Load ONLY the sheet you want. The reader skips everything else as it parses.
$reader->setLoadSheetsOnly('Notes');
$spreadsheet = $reader->load($inputFile);

printf(
    "\nLoaded only 'Notes': %d sheet in memory (%s), %.2f MB peak.\n",
    $spreadsheet->getSheetCount(),
    implode(', ', $spreadsheet->getSheetNames()),
    memory_get_peak_usage(true) / 1048576
);