I’m ready to e file and it’s asking me for a pin

There should be a form that comes up asking you to input a 5 digit pin number. This is part of the electronic signature that needs to be entered rather than a written signature. It came up for me but I have been using turbo tax for many years and it transfers from year to year. Just enter a 5 digit number and continue from there

To verify your identity for e-filing will use last year's adjusted gross income (AGI) as your PIN.

If you do not have a copy of your 2018 tax return you can get one from TurboTax it will have your AGI.  Follow thee steps to get a copy of your prior-year tax return. 

Sign in to TurboTax making sure you're using the same TurboTax account (with the same username) as in prior years. 

1. Select Documents from the navigation when it appears. 

2. Use the drop-down menu at the top of the screen to choose the tax year you want and then select Download PDF.   

This link  How do I access a prior year return? has additional information that you may find useful