Some do, some don't, and the rules change without notice. Facebook, Instagram and Twitter strip most EXIF on public posts but keep some internally. WhatsApp, Telegram (when "send as file"), Discord, email attachments, blogs, eBay listings — almost all keep EXIF intact. Never assume any service strips for you.
Try the tool
Drop a photo into the free EXIF Viewer & Metadata Remover — runs entirely in your browser, no upload.