Follow the steps to fill out the form accurately.

1. Press the 'Get Form' button to obtain the form and open it for editing.
2. Complete the identifying information at the top of the form, including the employer identification number and file number to ensure accurate processing.
3. In the 'Line A' section, prepare your payment in United States funds, ensuring it is payable through a U.S. bank if using a foreign check.
4. For 'Line 1', calculate the properly estimated tax based on the previous tax year or the current tax year, as per the instructions provided.
5. If applicable, complete 'Line 2' by entering the amount for the first installment of estimated tax; for those not required, enter 0.
6. Fill in 'Line 8' with any overpayments credited from prior years along with refundable tax credits you wish to credit as overpayment.
7. If someone else prepared the form, ensure the paid preparer section is completed with all requisite identification numbers.
8. Review the completed form for accuracy before proceeding to save changes, download, and print it to maintain a copy for your records.

Complete your tax extension documents online to ensure timely filing.