Accounts cannot be combined in TurboTax. If you are filing a married filing jointly tax return for two spouses who previously filed separate returns, select the most complicated 2017 return and transfer the information from it into the combined 2018 return. You will have to manually enter the information for the other spouse because it cannot be transferred from the 2017 return. Whoever is transferred into the 2018 return will be listed first on the joint return.