Enable DFF on Customer form and segments

1. First find the DFF that is attached to the Customer form.

Application Developer > Flexfield > Descriptive > Register
Query for Table Name: HZ_CUST_ACCOUNTS

Make a note of Title. This is the DFF that is attached to the Customer form.

2.  Application Developer > Flexfield > Descriptive > Segments
Query for Title: Customer Information > Uncheck Freeze Flexfield Definition > Save

3. Click on Segments to add new field(s) and to map with ATTRIBUTE column(s)
Here i have added  'My Field' > Finally Save

4. check Freeze Flexfield Definition [Reversal of Step-2]

5. Open Customer form to see the DFF fields added.
Receivables Manager > Customers > Customers
In the Simple Search, Select Customer Name > Go

At the Header level click on Details

Now you can see the field (DFF) we have just added at the Header level!