Add expires in to meta

Entrada WP Theme
#1

Where do I have to insert the following code line?

Dos it belongs in the child theme in the file header-center. php, or header-top. php or header. php?

Another option would be to include them in all three files.

What would be correct?

Thanks for your answer. Peter

#2

Hello,

You can add this in the child theme, by copying the header from main theme to your child theme.

Thank you