Hi Monica,
Can you elaborate more on what you mean by 'change the email subject'? Do you mean translating or changing the words of EasyBlog email notification title?
If yes, first you would have to find the language constant responsible for the respective email subject. You can locate the email template files here(JoomlaFolder/components/com_easyblog/themes/wireframe/emails/html/). There will be language constants in these email template files.
Once you have the language constant which you would like to modify, you can use this guide to create language string overrides.
After creating the overrides, try triggering new notification emails to see if the language strings are translated.
Hope this helps.

I guess it's in the post.new.php file. Which would be the language constant that corresponds to the subject of the email? I took the first and I have not observed any change in the notifications. Attached screenshot.

Thank you.

Hey Monica,
I'm not sure which email subject you are referring to. I have provided a screenshot link which points the respective email titles and their language constants.
http://take.ms/RLtCJ

Do note that COM_EASYBLOG_EMAIL_TITLE_NEW_BLOG_ADDED_WITH_TITLE is actually from the administrator language file. So you would need to add the override to this under Administrator instead of Site

If you are still having trouble, let us know which of these 2 constants you would like to change and provide us your backend access so we can help you out with this.

I want to change COM_EASYBLOG_EMAIL_TITLE_NEW_BLOG_ADDED_WITH_TITLE

I have done following the steps of the guide you provided me and not changed. Attached another screenshot where pointed out what I need to change.

Hey Monica,
Did you try to create the override for COM_EASYBLOG_EMAIL_TITLE_NEW_BLOG_ADDED_WITH_TITLE in the administrator section?
http://take.ms/DSlW6
Perhaps you can provide us access so we can check this for you.

I've got to change it. Thank you very much for your help Raymond.

Hey Monica,

You are most welcome. Glad to hear that your issue has been resolved now.

As a gentle reminder, kindly start a new thread if you have any other issue in the future so it will be easier for us to manage your inquiry. I will lock and mark this thread as resolved.