Create a suitable PCB footprint for the transformer and  save it with the name as the  manufacturer's part  number. Use a transformer symbol in the schematic and assign the name of the PCB footprint to the package attribute of the schematic symbol. For more on this, please read the EasyEDA Tutorial and then: [How to create findable Footprints and searchable Symbols](https://docs.google.com/document/d/e/2PACX-1vRBxS8uUSbskSIrJrNabh0A8qp0gZmWfUG7GlXX7oltY6XC9dukqS_BU-w4F-UarCNydPWOYz10VQ5V/pub)