Trigger Cutom Function on Child Sites

Thanks for this feedback. But as we discussed I have already this code. But my requirement is now different. I need to call a child site custom function from the main WP dashboard with the custom trigger.

Give you an example:

I have a custom page in the main WP dashboard. I have added a button on this page name “Sync+Update”. Now I want to trigger a hook by clicking this button and call a child site function.

In the child site function, there was added a code where calculate the custom size value with shell scripting. So when I want to recalculate this value I will click the button “Sync+Update”. And this time my child site function will save the value. and this value passes to the main WP which I have done already.

So please check my requirement once. I need a small difference requirement rather than the above feedback.

Thanks,