Your first job is free, start to finish: add the work and the photos, send the estimate, turn it into an invoice, send that, and record the payment. Nothing to sign up for and nothing to cancel.
To start a second job, or to change the free job once its invoice has gone out or it’s marked paid, you need Jobsheet Pro: $19.99 a month or $149.99 a year in the US (the App Store shows the price where you are). It is charged to your Apple Account when you confirm, and renews automatically unless you turn it off at least 24 hours before the period ends.
Once a document from the free job has left the app (handed to Mail or the share sheet, even if you cancel, or its preview screenshotted or screen-recorded), that job stays that customer’s. You can still change the work and send the estimate again, but you can’t switch the job to somebody else.
Email dlong8484@icloud.com and include what you were doing when it went wrong. It’s a one-person operation, so replies come from an actual human who wrote the code.