You can configure additional sending conditions with order tags and payment gateways.

You can set additional conditions both for Invoices and Packing Slips.

You can get more information from the links for each option below.

Order Tags (Include): https://support.simplio.app/knowledgebase/can-i-send-invoices-automatically-just-for-specific-customer-groups/

Order Tags (Exclude): https://support.simplio.app/knowledgebase/how-can-i-prevent-sending-invoices-automatically-for-orders-with-a-specific-tag/

Payment Gateways (Include): https://support.simplio.app/knowledgebase/can-i-send-invoices-automatically-just-for-specific-payment-gateways/

Payment Gateways (Exclude): https://support.simplio.app/knowledgebase/can-i-disable-automatic-invoice-sending-for-specific-payment-gateways/