Do something when user creates post (that’s pending)

If you want to target only one specific status change is probably easy / efficient use the
{$old_status}_to_{$new_status} filter, in your case:

add_action('draft-to-pending', 'do_something');
add_action('auto-draft-to-pending', 'do_something');

function do_something ( $post ) {
  // do something with the $post object
}

Related Posts:

  1. Check if post is being published for the first time, or is an already published post being updated
  2. What add_action reference should I be using or should I use do_action?
  3. remove_action on after_setup_theme not working from child theme
  4. Remove Actions/Filters added via Anonymous Functions
  5. Adding a second email address to a completed order in WooCommerce [closed]
  6. Trying to use add_action and do_action with parameters
  7. WordPress Theme Update Action?
  8. Extract image from content and set it as the featured image
  9. add_action in a function, is it possible?
  10. Using a private method as an action callback from within a class
  11. Refresh page after form action
  12. How to restrict actions and filters “properly” by conditions
  13. Add action hook conditionally – only when home.php in use
  14. Using add_filter() in Widgets
  15. How can I tell if I’m on a login page? [duplicate]
  16. Change meta tags programatically
  17. Convert hyphen to underscore in permalinks
  18. How to hook into the quick edit action?
  19. change a post status when users update posts?
  20. Reuse variable in hook callback
  21. Call to undefined add_action() in theme’s functions.php
  22. WooCommerce add_action hook results in 500 error
  23. How do I call wp_mail from HTML?
  24. Trouble using antispambot()
  25. How would go about if I just want a temporary function?
  26. Pass parameters to function through an action
  27. Accepted arguments value in hook functions
  28. How to select a page within admin?
  29. How to manage arrays from custom functions stored in functions.php?
  30. How do I pass arguments for multiple functions hooked to a single action?
  31. Which action hook to use for function?
  32. Custom HTML in specific category single page and its descendant categories
  33. Modify a function without editing template
  34. Don’t delete a page if it holds users
  35. How do I add Bootstrap and LESS to my migrated WordPress site?
  36. Contact Form 7 – Delay auto responds
  37. wp-comment author- url +, email filter hook
  38. Is there an alternative to get_template_directory_uri()?
  39. Reuse variable in hook callback
  40. Wait a result before enqueue
  41. Multiple Loops Meta Data
  42. Function added using `add_action()` not being called
  43. jQuery does not work
  44. Override the WordPress core function wp_referer_field
  45. Deprecated function get_user_by_email($email)
  46. Two functions with different arguments and add_actions, but identical code
  47. How to change this simple code so that it sends the email notification after payment in WooCommerce?
  48. I can’t seem to install Font Awesome locally [closed]
  49. Scripts not loading when using the wp_enqueue_scripts action
  50. Is there a way to prevent a function/method from being called outside a specific hook?
  51. Auto-Tweet if Type is ‘Status’ using OAuth
  52. problem loading stylesheets to wp_head dynamically
  53. current_user_can comma list vs OR (||) list
  54. Adding code before post title with the_title produces weird results
  55. How to properly refresh page after form action?
  56. Init action and refresh page after form action
  57. 400 Bad Request – JavaScript App calling Custom wp-json endpoint
  58. Changing where my author box is printed
  59. Insert Content Before div#main from the functions.php File
  60. Use add_action within template
  61. Problem in using Customizer
  62. Problem with custom function when I go back with the browser
  63. Replace admin header logo with an image
  64. New checkbox in custom widget isn’t saving data
  65. How do I find the code executed when wp_head() is called?
  66. template_redirect action only firing if logged in
  67. How to use wp_enqueue_script properly?
  68. Using get_terms for custom taxonomy in functions.php
  69. Fetch ids of live posts only (not posts with other statuses) and change status with a button in candidate dashboard
  70. Issue passing action class to nested function. Admin Columns
  71. Does hook have an effect on increasing the page load?
  72. Paragraph spaces in email template function
  73. How to Override Page Template if URL matches query?
  74. Save_post – Warning: Cannot modify header information
  75. What is the earliest Hook a Script can use?
  76. How do I trigger WP CLI DB export using a PHP function?
  77. Modifying a WordPress Plugin
  78. post value to function with Ajax and jQuery
  79. How do you insert code into the sidebar?
  80. How Do I Unhook This Parent Theme Function?
  81. If click on Save/Publish change Post Status to Pending Review instead Publish
  82. use add_action in a shortcode (gravity form – WordPress)
  83. wp_footer hook causing text to show on bottom of page
  84. How to change form action of wp-login page with a function
  85. Problem with email function
  86. Which method is more correct for removing WooCommerce Extensions menu item?
  87. WordPress hooks to call a function inside a construct
  88. True parameter but jquery register in header and not in the footer with wp_register_script
  89. Fatal error: Call to undefined function add_action() – an untouched problem
  90. Sending Messages Back to the Template After Processing?
  91. Pass arguments to function class with do_action()
  92. previous_post_link inside of a function?
  93. custom COOKIE on custom page
  94. function to return comma separated list of meta values
  95. Welcome Mails based on user role
  96. add variable to actions/functions across different files (woocommerce)
  97. How to hook wp_mail to add a custom email as BCC for each sent email?
  98. Change Post status based on custom field date +1 day
  99. delete_term is not working properly with add_action()
  100. How to get variable from other function inside class function using add_action for Ajax call