If you prepared your Federal return and it is showing a refund of $1, this generally would indicate that the total of the Federal taxes withheld from your pay and any other payments made was $1 more than the taxes you owe.
There are many reasons why your refund may be lower this year than it was last year.
This year, several tax credits have been lowered to amounts before the coronavirus pandemic—or eliminated entirely. This includes the Child Tax Credit, the Child and Dependent Care Credit, and more. Check if these changes are why your refund is lower.
Double-check your entries for income, taxes paid, and deductions to confirm they are correct. Compare the individual line items with last year's return as well, if applicable.
See this help article for more information.
You can preview your return before filing to find out how your taxes were calculated and to see the forms TurboTax has prepared from your entries. See here for details.