While most data import and export is only one-way between Entryless and Xero, supplier information is a two-way synchronization. New suppliers can be added in Xero and synced to Entryless, and new suppliers added through Entryless will sync to Xero.
If you imported all your suppliers from Xero to Entryless during the setup process, when a new supplier is created in Entryless, it will automatically be synced to Xero as a type of supplier in the contacts section of Xero.
Suppliers created in Entryless will be synced with Xero when you perform your normal bill synchronization process. Similarly, suppliers created within Xero will be synced to Entryless when you perform your normal bill synchronization process.