I need to add info and update form 8962 for 2018 return filed per IRS request. When I pull up the form it will not let me enter data.
Use this procedure for a Form 8962 requested by the IRS -
Only if the refund or owed amount has changed: Also include your Form 1040
The 8962 is only necessary and required if you have a 1095-A. So if you don't have a 1095-A then you have no need for the 8962.
Now my guess is that you are probably covered on your parent's plan, and they did receive a 1095-A with your name listed on it as a covered person under their plan. So basically you need their 1095-A. Then in the program you *MUST* indicate that you do have a 1095-A and work it through to enter all the data from that form, at which point the 8962 will be created and filled in by the program.