can i make a manual entry to a line on schedule d

If you are using TurboTax Online, no you cannot make manual entries on Schedule D.  If you are using TurboTax Desktop software, there are some fields that you can make direct entries to on Schedule D, as well other forms, schedules, and worksheets.  There are also some fields that while you can't make entries directly on Schedule D, you can make entries on Form 8949 or on the "Capital Asset Sales Worksheet" with the details of investment sales.  To make direct entries in TurboTax Desktop, click on the "Forms" Icon in the top right corner of the screen.  Select the form you want to make manual entries to from the list on the left hand side of the screen.