Pretty much everything's gone digital now, honestly. I'd say maybe 5% of agents still want actual printed pages, and even then it's usually older agents at traditional houses who just prefer it that way personally. Most submission guidelines will explicitly say "email query only" or "query through our online portal," so always check the individual agent's website first - that's your golden rule. I learned this the hard way a few years back when I printed out 50 pages to send to someone who'd already moved to email-only submissions. Waste of paper and ink, though I guess I used it to line some of my bee boxes eventually.
When you're querying, follow exactly what each agent's MSWL (manuscript wish list) or submission page says. Some want just the query letter in the email body, some want it as an attachment, some want you to paste sample pages directly into the email. A few bigger agencies use platforms like QueryTracker or their own submission system. The key is showing you can follow directions - agents notice if you ignore their specific requirements, and honestly it'll probably get you rejected before they even read page one. It's kind of like chess, right? You have to know the rules of the game you're playing before you can win. So yeah, don't print anything unless they specifically ask for it.