Robuta

https://tax2350.com/
Efile Extension of Time To File U.S. Income Tax Return Form 2350 with the IRS authorized efile provider ExtensionTax.com and extend your due date beyond June 15
tax formirsextensionefileextend
https://www.irs.gov/ht/e-file-providers/frequently-asked-questions-for-irs-efile-signature-authorization
e-signature content for some taxpayers who want to use forms 8878 and 8879 to sign electronic forms 1040 or filing extension using an e-signature
frequently asked questionsirs efileinternal revenuesignatureauthorization