Looking for the location to the redirect.
It doesn’t matter if it’s a CNAME or an A record. You can set up the subdomain as a CNAME or A record IP address, but set it to . Then create a Page Rule to match store.example.com and URL forward it with a 301 to example.com/store
But if you’re talking about mapping a subdirectory on your website to that subdomain, that’s something you’ll have to do at your server.