Tax Year Prior to 2020: I am a W2 employee but use a home office. I don't understand what is being asked of me in the Employee Home Office Worksheet, Part III "total wages from business?"

Employees with a W2 cannot claim the Home Office deduction.

I have a similar question. My fiance is filing W2 this year and was told that he might be able to write off interest on his home and possibly his truck. My mom usually files on turbo tax for us and is unaware of this. Is it something new? Do you have to have a 1098 to be able to write it off? 

If your fiance is a W-2 employee he cannot take a deduction for the use of his truck nor can he take a deduction for a home office.   If he has a mortgage and itemizes deductions on Schedule A (as opposed to taking the Standard Deduction) he can deduct his mortgage interest and property tax.  In order to receive any benefit, his itemized deductions would have to be more than the Standard Deduction ($12,200 for filing Single in 2019).