Do we have to sell the mutual funds if we have to move out of the foreign countries?

I don’t think so. US/ Canada do not have any such rule obligating you to sell mutual funds if you move out of the country. If the country you are moving into has a policy that prohibits you from holding foreign securities that need to be seen.

But there is no rule requiring you to do so in US /Canada. However, you may need to check whether your brokerage is allowed to operate from the country that you are moving to. If not, then you may have to look at alternatives.