Include root files into header files

If you are talking about the WordPress root, use:

include ABSPATH . "/extra-file.php";

ABSPATH is always the WordPress root, you can see that in your wp-config.php.

Related Posts:

  1. Can wordpress theme folder name be changed freely and nothing technically happens
  2. How to change the language for the front-end only?
  3. How do I add support to my theme for custom menus?
  4. How do I white label my self-hosted site created by wordpress?
  5. Switching themes without losing widgets?
  6. How to use media upload on theme option page?
  7. Multiple image logo for theme
  8. How do i structure my theme folder to avoid one huge list of files
  9. Loading template files from a subfolder in my theme?
  10. Hide Twenty Eleven Theme From Themes Page
  11. How to use scss in wordpress theme?
  12. How to get Ajax into a theme – without writing a plugin?
  13. Is it mandatory to have a link to the theme designer?
  14. How do I change Twenty Nineteen’s primary color without using the color slider in the theme customizer?
  15. WordPress as Backend, Laravel Front End: How to connect Routes?
  16. Updating custom theme that is built from scratch
  17. single.php change into a modal popup bootstrap wordpress
  18. Exclude stylesheet from admin
  19. How to tell a theme to use different .mo and .po files?
  20. Can I apply a WP theme to a specific custom page template?
  21. get_header(‘header2’) not working properly in child themes
  22. How do you remove Link backs on Theme settings page?
  23. Is it possible to use child theme of child them?
  24. Disable Sidebar in the Product Page in Storefront Theme [closed]
  25. Theme broken after upgrading to WordPress 4.5, missing stylesheet?
  26. Do not show excerpt in post content
  27. Do we have rights to edit the source of the templates which are in wordpress.org?
  28. What’s the order of loading wordpress elements?
  29. How to add pagination to my code?
  30. Creating new templates in child themes breaks layout
  31. How do I tell how popular a theme is?
  32. Force theme or disallow theme change
  33. How to put a Worpdpress theme in spanish (having the po file)?
  34. How to run WordPress from other location on the same domain
  35. Custom options below pages/posts editor?
  36. Fatal error with a theme
  37. WordPress theme options and insert default value for serialize data
  38. How to change only one javascript function in wordpress child theme?
  39. Woocommerce StoreFront Showing Incorrect Subtotal in Customer Total
  40. Depending on third party plugins for theme functionality
  41. What is the correct way to integrate wordpress with another php application?
  42. How can you showcase premium themes to clients without having to pre-purchase the theme?
  43. Functions containing parameter ‘yourtheme’
  44. The Cost of Installing Custom Themes
  45. Can I create a child theme from a premium theme without losing my posts and page etc that I already have?
  46. Cant remove white space on my wordpress [closed]
  47. wordpress theme install failing
  48. WordPress suddenly creating theme errors
  49. Re-skinning Site
  50. How to reset a custom theme
  51. Warning : Invalid argument supplied for foreach() in theme php on line 56 [closed]
  52. get_the_post_thumbnail() produces different HTML on same arguments
  53. Why submenu item’s background color is not changing by css?
  54. .PO file is found but I don’t see translations: how to debug the problem?
  55. Cannot figure out what element header color is in wordpress theme [closed]
  56. How to edit the font color of the H1 on a single page?
  57. An unexpected error occurred when add theme
  58. Searching for themes that post full article on home page by default
  59. Cannot see theme in my search
  60. Posts & page twice display
  61. What login/password do I need to install a wordpress theme?
  62. How to remove date, author and comment count from Chameleon search results page
  63. Index page is not working
  64. get_pages Not accepting my query
  65. Date based CSS/theme
  66. Custom fields in post later used in loop
  67. How to create a theme that can be updated by people using the theme on their site
  68. Functions.php error – when trying to change the theme
  69. Make a menu item unselectable
  70. Can I use non-wordpress themes in WordPress?
  71. Set custom directory in theme for page templates
  72. how do you add a gallery to the homepage without using a post or page?
  73. How to change WordPress theme outside of admin? Can’t access dashboard
  74. fixing page URL’s
  75. Don’t prepend WordPress base url to image paths
  76. Change name of WP content > Themes folder
  77. How to get dynamic template-function generated CSS into HEAD?
  78. Password Protected Page + Showing Different Page If Not Authenticated/Authorized
  79. Show part of front page on another page [closed]
  80. Determine Featured Image Size in header
  81. Premium theme – hardcoded url?
  82. Any Mobile Theme Switcher – Theme not complete (Stylesheet missing)
  83. Categorising themes by folders in backend
  84. My site looks different when activating new theme
  85. Child theme after CSS modification
  86. How to make a website like the ones in theme demos? [closed]
  87. How to create an Single-Portfolio page?
  88. Page structure using The Customizer Api
  89. theme 2016 – customize css – nothing happens
  90. Can’t upload the theme
  91. Divi theme including javascript
  92. “Parse error: syntax error, unexpected” and the WordPress Theme Editor no longer working!
  93. Installing themes from an external website [closed]
  94. Best Practice Jumbotron Image for WordPress ~ Responsive
  95. How to make a page extend full screen [closed]
  96. Should you directly edit Template Parts and Templates from themes?
  97. Remove ALL HTML from single page
  98. Remove Google Fonts from parent theme within a child theme [closed]
  99. register_nav_menus syntax error, unexpected identifier “register_nav_menus” in
  100. RTL in posts only [closed]
tech