Are you self-employed or do you get a W-2 from an employer? If you are self-employed you can enter business expenses on a Schedule C.
If you are a W-2 employee, you cannot deduct job-related expenses on a federal return.
Job-related expenses were eliminated as a federal deduction for W-2 employees by the tax laws that changed for 2018 and beyond. Your state tax laws might be different in AL, AR, CA, HI, MN, NY or PA.
If you live in a state that lets you deduct job-related expenses, the information will flow from your federal return to the state return, so enter it in Federal>Deductions and Credits>Employment Expenses>Job-Related Expenses
Federal
Are you a salesperson for a company and receive a W2? If so, then there is nothing at all to report on your return.
If you receive a 1099-NEC for this work, then you can claim mileage or actual expenses for the truck and claim your other expenses. This would not be a loss, it would be a business expense.
When you say about a property loss, that would apply if you had a loss of a business asset, such as totaling your truck.
State
Some states do allow you to claim employee business expenses. If so, as you walk through the state interview questions, TurboTax will ask you about your employee expenses.