Application allows mass record sending and PDF generation. It can be done with mass Sync Status field updating. The Sync Status field contains the following values:

Not Synced – record was not sent to sevDesk 
Synced – record was sent to sevDesk as Draft
In Approval – record is in Approval 
Generated – record was sent to sevDesk, marked as Completed and PDF was Generated

Values which can be used to control process:
To be Synced – mark the record as ready to sync. It will be sent to sevDesk as soon as the system resources are available.
To be Generated – mark the record as ready to sync and for PDF generation. It will be sent to sevDesk and PDF will be generated as soon as the system resources are available. 

Sync Status fields are listed below:
Quote.cwharf_sevdesk__Sync_Status__c controls Quote sync process.
Order.cwharf_sevdesk__Order_Sync_Status__c controls Order Confirmation sync process.
Order.cwharf_sevdesk__DeliveryNote_Sync_Status__c controls Delivery Note sync process.
Order.cwharf_sevdesk__Sync_Status__c controls Invoice and Credint Note sync process depends on cwharf_sevdesk__Type__c field.
Order.cwharf_sevdesk__InvoiceCancellation_Sync_Status__c controls Invoice Cancellation sync process.

The simple example of bulk Order Confirmation sync is described below: 
1. Open Order list view:

2. Mark the records as To be Generated and click save

3. After the described actions, the system will start the process. The process is finished when the record status is marked as Generated