Since you're out of the country, you qualify for an automatic extension until June 15th for Tax Year 2019.
When you do file your return on or before June 15th, you'll need to attach a statement to your return that explains that you were eligible for the two-month extension.
Please see the TurboTax Help article "How do I file an IRS extension (Form 4868) in TurboTax Online?" for guidance.