When filing as married filing jointly you can claim a personal exemption for yourself and your wife even if she didn't have income. Then you can also claim a dependent exemption for each child you claim as a dependent. For example: if you had a wife and two children you would have four exemptions total. (two personal ones and two dependent ones)
Please view the TurboTax FAQ below for more information.
https://ttlc.intuit.com/replies/3299967
