You can use one of your available filesystem disks to write the sitemap to.
use Spatie\Sitemap\SitemapGenerator;
SitemapGenerator::create('https://example.com')
->getSitemap()
->writeToDisk('public', 'sitemap.xml');
You may need to set the file visibility on one of your sitemaps. For example, if you are writing a sitemap to S3 that you want to be publicly available. You can set the third parameter to true to make it public.
use Spatie\Sitemap\SitemapGenerator;
SitemapGenerator::create('https://example.com')
->getSitemap()
->writeToDisk('public', 'sitemap.xml', true);
A sitemap index can also be written to a disk:
use Spatie\Sitemap\SitemapIndex;
SitemapIndex::create()
->add('/pages_sitemap.xml')
->add('/posts_sitemap.xml')
->writeToDisk('public', 'sitemap.xml');