Can I provide IPOS with information or observations regarding someone's patent application which I would like the Examiner to review?

You could do so by submitting a third party observation regarding patentability of the application:
In a letter explaining how the prior art is of relevance to the patent application
Do note that reasons and any relevant documents to support the observations should accompany the submission.
When can this be filed?
Any time after the date of publication of the application and before the issuance of the examination report, search and examination report or supplementary examination report.
How can this be filed?
It must be submitted via ad-hoc correspondence module in IPOS Digital Hub. The document type “Third Party Observations” will allow these supporting documents to be furnished.
Is there a fee?
There is no fee for submitting a third party observation.
How will the information or observation be considered?
It will be considered by the examiner during the examination process.
If it is assessed by the examiner to have an impact on determining the patentability of the patent application, the patent applicant may formally respond via a response to the written opinion in Patents Form 13A.
Can my identify be kept anonymous?
The information or observation may be submitted via a registered patent agent or lawyer without disclosing the filer’s identity.
For more information, please refer to Examination Guidelines for Patent Applications found here