An easy way is to add a notification or toastr widget in navigation layout of the page.
The notification widget below is pretty well documented. 

https://marketplace.mendix.com/link/component/2856

But there are several others also, when you search for toastr in the appstore.
 

Hi Sekhar,

I don't know if i understand your question correctly, but their is a possibility to add (pop up) messages using microflows.
Perhaps you could try that? :)

Please Give ans this:

https://forum.mendix.com/link/questions/109839

Use a microflow to show the message from an configurable entity and show the page. 

Why is it not possible with this?

There is another way as well, which I have done it and working for a different requirement. 

But first, please explain why show a message and show a page does not work for you?

UPDATE

if you want to show in footer, then in your layout pages, try to add a container below your main layout

You can have a dataview with microflow to retrieve the object which stores the configuration for contact address

With dataview you can show that email id

1- Add an Entity for the Admin with an attribute for the configurable text Call it (ConfigText)

2- in Admin Settings Page You Add an Data View With Data Source From You Entity Here the Amin Can Add New ConfigText 

3- Admin Save the New ConfigText

4- In the Place You Want to Show Your Text You Add ListView with DataSource From Our New Entity 

5- Choose First 

6- Choose descending

7- Save 

Now You Are Ready To Go 

This is included in module SystemManagement.

You can copy-paste the code or better, import that module into your application.