How to block my business email account from people creating an email address with using my business name?

People have created email addresses with my business email address and sending rude and disguisting emails to other people. There has to be a way to block this from continuing.

There's two ways that people can send an email using an email address that belongs to you. One is called "spoofing", where they make their emails 'look' like they're coming from you, when in reality they're coming from someone else. There's no way to stop this at all, because it's happening from someone else's computer entirely, and you're totally out of the loop. All you can do is explain to people that you are not the one who sent those messages.

The second way is if a hacker has somehow taken over your email address. Either they have learned your password, or you have a virus on your system that is sending the email from your computer. Run a full virus scan on your computer. AFTER the virus scan has run, change your email password. You want to change your email password AFTER the virus scan so the virus does not get the new password. If that was the problem, the emails should stop. Make sure NO ONE ELSE has your password - even one person having a password to your email is a security risk.

You may also want to simply create a new email address. If you work for a larger company, ask your IT department to create you one. If the email you use is free, simply create one yourself and let everyone on your old email list know that you've changed.