Z4K Orders Manager

Yes. WooCommerce must be active, with High-Performance Order Storage (HPOS) turned on. HPOS is the default for new WooCommerce stores; you can check it under WooCommerce > Settings > Advanced > Features. Without it the plugin shows a notice and stays idle.

By default, yes: it sends its own editable versions of the WooCommerce customer emails listed above. Each one can be switched back to the WooCommerce email on the Mail tab, under WooCommerce Email Templates.

Where no web server can serve them, whatever the server is (Apache, nginx, LiteSpeed, IIS): into a folder of the plugin's own outside the public web folder, by default next to the WordPress folder. When the server does not let PHP write outside the web folder (for example open_basedir), they are kept encrypted in uploads/z4k-private instead, where a direct address returns only encrypted data. To choose the parent folder yourself, add define( 'Z4KOM_PRIVATE_DIR', '/path/outside/the/web/root' ); to wp-config.php; the files move there by themselves. The Transfers tab and Tools > Site Health show which mode is used. Files get random names and WordPress's "private" status, so they are not listed in the REST API, search or attachment pages, also while the plugin is deactivated. Shop staff (administrators and shop managers) can see them in Media > Library and on the Transfers tab; a customer can open only their own, through the plugin's viewer. When you back up or move the site, include that folder (in encrypted mode the key is kept in the database).

A little, to protect customers who have already paid:

• A payment gateway that reports "failed" or "cancelled" for an order that is already paid is ignored and the order keeps its paid status (an order note records it). Staff can still change the status by hand.
• The "payment failed" email is held back 60 minutes and the "order cancelled" email 12 hours, and is dropped if the order has been paid in the meantime. Both delays can be changed or set to 0 on the Mail tab.
• Unpaid orders are cancelled by WooCommerce's own stock timer as usual. On Settings you can keep them payable for longer (Unpaid Order Grace Period, off by default), and you can turn on cancelling old on-hold orders after a number of days (off by default).

"Scheduled" is the plugin's own order status. While the plugin is deactivated, WooCommerce does not know that status, so those orders are not listed until you reactivate it; nothing is lost. When you delete the plugin, every Scheduled order goes back to the status it had before (processing or on hold) with an order note, without emailing anyone.

Everything stays on your own server. In the WordPress database: delivery records; an activity log of order actions (with the staff user and IP address); and the Mail Log, which is on by default and records the recipient, subject, time and result of every email the site sends (the message itself only if you turn that on). On disk: the payment-proof files customers upload, in the plugin's private folder (see "Where do payment proofs go?"). Each log has its own retention setting, and the Mail Log can be switched off on the Mail tab. If you turn on the Tracking Pixel option on the Mail tab (off by default), delivery emails include a small image, served by your own site, that marks the delivery as opened. Suggested privacy-policy text is added under Settings > Privacy.

Deleting the plugin from the Plugins screen first moves Scheduled orders back to processing or on hold, then removes its settings, delivery records, the payment-proof files customers uploaded, logs and scheduled events. If Orders Manager Pro is installed, nothing is removed, because Pro uses the same data.

A separate paid plugin from z4market.com with a support desk, license-key stock, shipping and cash on delivery, customer profiles, email marketing and a team portal. It replaces this plugin and keeps your settings and data.