Problem:

What is the best solution for add a shortcode that contains a value that can be added to any page of the site?

Solution:

In most theme, there should be a widget can display in all of your website pages, for example WordPress default theme 2020, you can try these:

1) Dashboard-> Toolset-> Content Templates, Create a content template "my-ct", display the text and value you want:

https://toolset.com/glossary/template/

2) Dashboard-> Appearance-> Widgets, in the Footer sidebar, you can add a text widget, and display above content template's shortcode:

[wpv-post-body view_template="my-ct"]

Relevant Documentation:

https://wp-types.com/documentation/user-guides/views-shortcodes/#wpv-post-body