You will enter a PIN when you go through the steps to file your return. The Self-Select PIN (Personal Identification Number) method allows taxpayers to electronically "sign" their e-filed return by using a 5-digit PIN. See the following:
https://www.irs.gov/e-file-providers/self-select-pin-method-for-forms-1040-and-4868-modernized-e-fil...
