How to copy page/post from one theme to another?

If you used the wordpress code editor, it means you modified the actual files. You need to connect to your cpanel > file editor ( or via ftp ) > wp-content > themes / wordpress 2022 and find the files. Copy them to your child theme folder.

If you updated the “wordpress 2022” theme, these are likely gone. This is why is important to use “child” themes, so your modifications do not get overwritten on an update.