I am planning to buy turbotax home and business version with 12 returns. Will tax expert be helping me or is it file by own ?

TurboTax have a variety of products. If you take the download version Home & Business, you will have to file it alone. 

If you need a Tax expert to look over your return and help prepare it, you will need to use the Full service package on the Online Version. Please see the details of the benefits for the full service package. 

Thank you for choosing TurboTax.