I am trying to create an FTP user that can manage the /var/www directory which is owned by www-data.
I have seen a post suggesting this:
chown -R newuser:www-data /var/www
How do I create a user and allow that user to manage /var/www without changing ownership of that directory?
www-datagroup may be what you're looking for ...
myuser:www-datasetups where I own the files and can edit but so can Apache where it needs to. That's a permissions issue that can be resolved easily, Apache doesn't need to own the directory it just needs access to directories and such where it needs ti (based on what your site's application needs are)