When you make a report, reddit will — eventually — give you a reply letting you know if the person did or didn't violate the rules.

For example, one I've gotten a little while ago:

Thanks for submitting a report to the Reddit admin team. This content has already been investigated from a previous report. After investigating, we’ve found that the reported content violates Reddit’s Content Policy and have taken action.

If you’d like to cut off contact from the account(s) you reported, you can block them in your Safety and Privacy settings. You can also hide any posts or comments you don’t want to see by selecting Hide from the “…” menu.

If you see any other rule violations or continue to have problems, submit a new report to let us know and we’ll take further action as appropriate.

Thanks again for your report, and for looking out for yourself and your fellow redditors. Your reporting helps make Reddit a better, safer, and more welcoming place for everyone.

For your reference, here are additional details about your report:

Report Details

Report reason: Harassment
Submitted on: 03/20/2023 at 12:37 AM UTC
Link to reported content: https://mod.reddit.com/mail/perma/1fqqhp/22y8m7

-Reddit Admin Team

This is an automated message; responses will not be received by Reddit admins.

In this case, I had to report the user's comments in the subreddit, but after banning them, they were nasty in modmail so I reported that and got that.

The way to know if they got a warning or tempban from that is to click the modmail link (in your report, obvs you can't see my modmail) and click the user from there - if they're still available, a warning. If they're suspended, they've been previously warned and now it's a 3, 7, ot 30 day ban. :)