I have Premier. How can I upgrade to Business as I need to file a Form 1041.

[sceptre2017]

To prepare a Form 1041 you will need a completely different program.  Please make sure you read the system requirements prior to purchasing the program, as you cannot install it on a MAC. Also, the business program is only available via desktop version. 

Turbo Tax Small Business Taxes

https://turbotax.intuit.com/small-business-taxes/