I am entering my 1095-A info.family of 3 but my form 8962 shows family member 2. Because of that it looks like I need to pay 1800, how can I edit the number of members ?

You could share a Marketplace policy with any of the following people who aren't on your taxes:

• Someone with whom you share custody of a child
• A former spouse
• A person who now claims your child as a dependent on their taxes
• A person you used to live and file taxes with
• A parent or an adult child

If someone on your 1095-A is not your dependent or your spouse and does not file taxes, you'll have to repay any discount you got to help pay for health insurance.   If you shared the policy with another taxpayer, you can allocate the costs of the policy to their tax return.  

After you enter the 1095-A, you can check the box that says I shared this policy with someone else who is not on my return.   After checking that box, you will be allowed to adjust what was reported on your 1095-A.   For more examples on how to deal with shared policies, see this Help Article.