Set default values for any field
Using Customize Form, we can set a default value for any field of any Doctype in ERPNext.
1. Open Customize Form using awesome search bar or via Menu options of any DocType. This will open a screen where you can view all the fields that comprise in this DocType.
2. Expand the field for which you want to store a default value and enter it under Display -> Default
Check out the below GIF where we have set default value as Stores - ETL for field "Default Source Warehouse" in DocType Stock Entry:
To learn more about customisations in ERPNext, check out this link