Adding reference to Journal Entry

To link a Journal Entry to the document* of choice, expand the row you want to insert a reference with and choose the Reference Type and Reference Name.

Refer to the GIF to illustrating the same:

List of Documents one can link to a Journal Entry:

Sales Invoice, Purchase Invoice, Journal Entry, Sales Order, Purchase Order, Expense Claim, Asset, Loan, Payroll Entry, Employee Advance, Exchange Rate Revaluation, Invoice Discounting, Fees.