Where do I enter Virginia 529 credits on the Virginia state form? (Not distributions.)
In your state section go to the interview screens until you reach a page titled "Here's the income that Virginia handles differently".
On this page, scroll down to the Education section.
Select Start (or Edit or Revisit) next to Commonwealth Savers (Section 529) Plan or Virginia College Savings Prepaid Tuition (Section 529) Plan.
Follow the prompts to enter your 529 account information and the total amount of your contributions for the tax year. You can deduct up to $4,000 per account per year, with an unlimited carryforward of any undeducted amounts to future years.