PHP triggered task execution

PHP triggered task execution is like this. how can I enable PHP to execute a specific code when the first person accessing the website on the first day of every month does not work until the first day of the next month, the first visitor executes a specific PHP triggered execution task.
The problem is.
How can I enable PHP to execute a specific code when the first person accessing the website on the first day of every month fails to access the website,
Until No. 1 in next month, the first visitor will execute a specific code to share it: More