I have inherited 401k and wondering how much extra I should take out for Iowa and Federal on top of the already deducted amounts?

Are you referring to the amount you need to withdraw from the inherited account (e.g., the RMD or otherwise) or the amount you should pay in estimated tax?

For Iowa, see https://tax.iowa.gov/estimated-income-tax-payments

For Federal, you can avoid an underpayment of estimated tax if:

1) your estimated tax payments equal or exceed 90% of your 2022 tax liability; or

2) your estimated tax payments equal or exceed 100% of your 2021 tax (110% if your 2021 adjusted gross income was more than $150K); or

3) the balance due after subtracting taxes withheld from 90% of your 2022 tax is less than $1,000 or

4) your total tax liability for 2022 is less than $1,000