How does the Canonical attribute work?

Question

Search Engine Optimization

Hello community.
I was looking for where to buy a link to my site and came across a company that provides such a service.
They sent me a list of sites and everything would be fine, but it confuses me that most of their sites use the canonical attribute in a strange way.
Those. if the article has a site.ru/blabla/ link, then it will have rel="canonical" to the main one.
Therefore, I ask you to explain how this attribute works and whether it is worth buying such links.
Of course, I have already read articles that it is used to glue duplicate pages, but how will the links placed on this page behave in this case?
And how will PS react to these links?
Clarify please.

Answer 1

The news will be bad, buy links directly on the exchange and manually select sites

Answer 2

Such links simply will not be taken into account. They will not transfer weight and you will waste your budget. See competitors, what backlinks they put and on what pages, see the dynamics with which their links are growing and you can see where they buy links (if they buy at all) CheckTrust is a good service to see where competitors buy links)