Yes you can file a Joint return. Joint is the best way to file and has the lowest tax rates. Married filing Separate is the worst way to file and you lose several credits. Yes her daughter is your dependent now.
If she files Schedule C for her business you include it in the joint return.
Here's some general info on getting married. Did you both use Turbo Tax last year?
You can not transfer from or combine 2 returns or accounts. Just pick the return for the spouse that has the most complicated return to enter or has any depreciation or business or more investments. Or use the account for whoever you want to be listed first going forward (by the way you can not change the order of the names). Then add the other spouse's name, ssn and info to it.
You should usually file a Joint return which is only 1 return combined for the both of you. Make sure to stick with this one account for the future. Just ignore the other spouse's account.
Getting Married FAQ
https://ttlc.intuit.com/community/tax-filing-status/help/what-does-getting-married-mean-for-my-taxes...
And info on Getting Married…..
http://turbotax.intuit.com/tax-tools/tax-tips/Family/Getting-Married/INF12006.html
Is it better to file Joint or Separately?
https://ttlc.intuit.com/questions/1894449-is-it-better-for-a-married-couple-to-file-jointly-or-separ...
This answer has been verified for accuracy by an Intuit expert employee
