I purchased a customer list(Section 197 Intangible). How do I amortize it in TurboTax Deluxe?

Your section 197 intangible is amortized over 15 years.

Amortization is a business expense and you need to upgrade to TurboTax Self-Employed to enter this intangible asset and amortize it.

Please read this IRS document for more information:

https://www.irs.gov/businesses/small-businesses-self-employed/intangibles

• In TurboTax Self-Employed, under Business Assets, go to the Asset Summary and click Add an Asset
• On the next page, click the radio button next to Intangibles, Other property
  
• On the next page. choose Amortizable Intangibles and click Continue to enter the details of the asset
• TurboTax will calculate the amortization and include it in your Schedule C.