How to filter posts by category?

Hello,

I am creating a post grid box shortcode, but I can’t find a way to filter the posts by category. For instance: I want to show only posts in the News category, not posts in the Opinion section. Is this possible?

I am also having trouble taking the tags off the post, even though the code reads “false”. Let me know if anyone can help with either of these questions!

Thank you kindly.

The page I need help with: [log in to see the link]