如何在Linux / var / www中设置权限以允许从PHP-Apache自动覆盖

I would like to allow users to upload new versions of documents via a web app. However, the permissions are not currently set up to allow any file within the particular folder to be overwritten by default. Is there a way to set up the default permissions or other settings of all current and future files to automatically be replaced by a new file with an identical name, and path obviously. I would like to allow users to upload new versi