If you are using the WordPress plugin named SMTP to configure your SMTP settings, and you are having problems with customizing the from email address and name that’s a known issue. The SMTP WordPress plugin uses the first name and email address in your WordPress database by default when sending email. You’ll need to edit two lines in the SMTP plugin to fix this. It’s an easy fix.
First go into your WordPress admin screen. Under Plugins select Editor.
From the dropdown on the right select SMTP and click the “Select” button.
Scroll down in the large text area and find the following two lines:
$phpmailer->From = $admin_info->user_email;
$phpmailer->FromName = $admin_info->display_name;
Simply put a pound sign (#) in front of those two lines.
#$phpmailer->From = $admin_info->user_email;
#$phpmailer->FromName = $admin_info->display_name;
Then click the update file button at the bottom. Emails should now be sent out using the username and email address that you specify in the configuration.