According to Intuit, esignature only supports current year tax returns, which means you can't use it for 2018 or 2019 returns.

You should also make sure you buy just enough for this calendar year because any used balance will expire on Dec 31 and can't be carried over to 2022.

https://proconnect.intuit.com/community/manage-integrations/help/intuit-esignature-faqs-resource-gui...