How to pass function from parent page to child page

I want to pass the functions from the parent page to the child page. If anyone has the experience, please help me now.

All communication amongst components should be done using @Input and @Output bindings or via services that are injected by all interested parties. Never attempt to call internal component functions from outside the component - that breaks the fundamental point of having components in the first place - encapsulation.

Any component you write must be agnostic (“ignorant”, if you prefer) about where it is hosted. If that’s not possible, you’ve drawn the component lines in the wrong place, and everything needs to be merged into a single component.