I want to make page visible but content should not appear. Page should show that you are not logged in you don't have permison to view this page. So when user login he can see that page
which page ? is it any page on your forum ? if so see below setting
admin panel >> configuration (settings) >> Login and Registration Options >> Force Users to Login --> yes
I want to block 1 page only not all pages
What kind of page? Default or custom one?
How can I make custom page? I want to block custom page
when i run naor donation plugin i see
"Donations settings are not set the right way, please contact the Admin"
how to fix this
You'd have to edit the page and do like this;
if(!$mybb->user['uid'])
{
error("Sorry, but we require you to login to view this page.");
}