If the IRS website does not work then you cannot. IRS has shut pone service down. Either wait until things return to normal or print and mail the return but even mailed returns are not being processed currently.
https://www.irs.gov/identity-theft-fraud-scams/retrieve-your-ip-pin
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**NOTE*** Due to the Corona virus the IRS is operating short staffed. All field offices are closed and some processing centers are all but closed. Any tax return that requires hand processing will probably have long delays. Mailed returns are not being processed at all at this time. Most phone service has been curtailed.
https://www.irs.gov/newsroom/irs-operations-during-covid-19-mission-critical-functions-continue
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