How to change date format

Hi,
by default if you select “Text only” for the post metas design a predefined date format
y M, Y
If you select “Button and text” the date format used will be the one you choose in wp settings (a).

Though you can use a theme filter hook, returning false or empty string, to revert this and always use the (a).
Filter hook:
tc_meta_date_format

how to use filters?
https://docs.presscustomizr.com/article/26-wordpress-actions-filters-and-hooks-a-guide-for-non-developers

Hope this helps

The Button and text is not what I need. Can you please help me with the filter? I read the page you’ve mention, but I’m no expert in coding and php.
Thank you!