what is post meta of this plugin ?

hey .
i am using Post Pay Counter https://wordpress.org/plugins/post-pay-counter
and he asking insert post_meta to count visites

The plugin does not keep track of visits, it can only keep it in mind when computing the payment. You either need to have a plugin who keeps track of visits, and put the post_meta name of the field in which it stores the visits (must be a number)