Yes, you can file an extension in TurboTax, but you must file it by the tax deadline date of May 17, 2021.
To file the extension, take the following steps in TurboTax Online:
1. Sign into your Tax Return and leave it at the Tax Home Page
2. Select File an extension at the bottom of the column on the left side of the screen. (See Sample Screenshot below)
3. Follow the onscreen instructions to e-file your extension.
For more information, please see this link: How do I file an IRS extension (Form 4868) in TurboTax Online?