As long as you are filing jointly, it is okay if the Spouse information isn't included on Form 4868. However, if there is a chance you may file separately, the spouse should file an extension of their own.
To do so, you can create an additional TurboTax account for the spouse (just for the purposes of filing an extension).
The information below will help you create a new TurboTax Online account and file another extension.
Alternatively, you can download and print Form 4868 from the IRS Website.
[Edited 4/12/2019 | 12:25 PM EST]
