Go through the following steps to send out direct emails to users in Jira:

1. Navigate to Administration > System > Send email.
2. Select the recipients of the email. You can choose to send an email via Project Roles or Groups. For example, to send an email to everyone who uses Jira, you can select the jira-software-users group (if it is the group that all of the users are in).
3. Type in your email Subject and Body.
4. Check the Bcc checkbox if you do not want people to see other recipients' email addresses.

5. Click on the Send button to send the email, as shown in the following screenshot:

This completes the steps to send emails to users.