Create a Transaction Saved Search to Display "Days Taken" from Sales Order Date to Invoice Date

1. Navigate to Reports > Saved Searches > All Saved Searches > New.
2. Select Transaction as the Search Type.
3. Enter a Search Title and set the following:

a. Criteria tab > Standard sub tab:
    - Type = Invoice
    - Main Line = T
    - Created From : Type = Sales Order
    - Date = user preferred date range

b. Results tab > Columns sub tab:
    Field | Custom Label
    - Date| Invoice Date
    - Created From Fields... Date | Sale Order Date
    - Type
    - Number | Invoice Number
    - Name | Customer Name
    - Amount
    - Formula (Numeric) | Formula = {trandate}-{createdfrom.trandate}| Days Taken

4. Click Save & Run.