Hi,
Incase of correcting any errors post application submission, you may raise the an online webform informing IRCC about the matter and depending on the issue, you may receive further instructions. The link is as follows:
https://secure.cic.gc.ca/enquiries-renseignements/canada-case-cas-eng.aspx
or you can re-submit a few immigration forms yourself (that you filled while application filing online) with the correct information such as IMM 0008e, a letter of explanation etc.