It depends. Your refund may go up or down. If you used TurboTax to complete the forms you can review an updated page 2 of your 1040, which will show your new refund amount.
The documents you faxed to the IRS are either part of the reconciliation of the Advanced Premium Tax Credit or you needed to account for the allocation of your tax credit if your marketplace policy was shared with another taxpayer. This will delay your refund. The notice you received from the IRS provides information on how long your refund will be delayed. More than likely it's 6 to 8 weeks from when they receive your documents.
See the TurboTax FAQ below for more information. The same information applies to the 2017 tax year.
https://ttlc.intuit.com/replies/5824742
