Recently I was refused by the UK. Now I want to apply for a Canadian visit visa.
My question is, how many days later does the UK embassy share the refusal information with other countries?
That information is not public knowledge.
However, if you are trying to lie in the Canada application saying that you didn't get a visa refusal and they find out, then you will be held liable for deception, which may include a ban.
So, see what was wrong with the application, rectify the things you can and be truthful about refusal.