I personally received email from IRCC after I submitted my application few days ago. Here’s what it says:
This is an automated message. Do not reply to this email.
Hello,
This email confirms that you have successfully submitted your citizenship application.
We’ll review your application to make sure you
• provided all of the information we asked for
• uploaded all required documents correctly
• paid the fees
We’ll send you a confirmation email (an acknowledgement of receipt or AOR) once an agent starts reviewing your application.
• It can take some time before you receive the AOR.
• Check your email regularly to see if you’ve received it.
Sign in to your account at any time to
• download a copy of your application
• find out what you can do after you apply
Thank you,
Immigration, Refugees and Citizenship Canada