Can I just share links to articles instead of copying them?
Yes, you can always share links to freely available resources, if they have been made available by the copyright owner. If you have found a resource where it seems unlikely the copyright owner gave permission for it to be there, be cautious of sharing it.
Sharing links to paywalled content is the preferred method as the end user would need a valid login to access the resource. This is often the best practice for open access articles.