Create a new migration
php artisan make:migration change_description_products_table
In the new file add this to the function up():
Schema::table('your_table_name', function (Blueprint $table) {
$table->text('your_field_name')->nullable()->change();
});
Make sure you install doctrine/dbal because it’s required for this.
composer require doctrine/dbal
Now you can run your migrations.
php artisan migrate