Create a Custom Formula Field that Sources a Related Record Linkable

 The following formula can be used to make any custom field that sources in a related record linkable.

 

In this example, the following formula was added to a custom field that resided on the Task record.  The task record has a Transaction field which allows you to link the task to a transaction record.  The below formula will populate the transaction number of that record and also make it linkable.

 

'<a href="https://system.netsuite.com/app/accounting/transactions/transaction.nl?id=' || to_number({transaction.ID}) || '">' || to_char({transaction.tranid}) ||' </a>'

 

Note:

I would recommend setting the Display Type equal to 'DISABLED' in the custom field.  This will prevent the field from being edited by users.