faveo/vendor/maatwebsite/excel/docs/export/freeze.md

Freeze rows

If you want to freeze a cell, row or column, use:

// Freeze first row
$sheet->freezeFirstRow();

// Freeze the first column
$sheet->freezeFirstColumn();

// Freeze the first row and column
$sheet->freezeFirstRowAndColumn();

// Set freeze
$sheet->setFreeze('A2');