Tax Year Prior to 2020: I need to know how to claim perdiem i am a truck driver

It's entered in Job-Related expenses section for Form 2106 (see below).   The standard meal allowance (per diem) for 2016 is $63 a day ($68 for travel outside the continental United States). This is for overnight travel.

You can use a special standard meal allowance if you work in the transportation industry. You are in the transportation industry if your work:

• Directly involves moving people or goods by airplane, barge, bus, ship, train, or truck, and
• Regularly requires you to travel away from home and, during any single trip, usually involves travel to areas eligible for different standard meal allowance rates.

Travel for days you depart and return.    For both the day you depart for and the day you return from a business trip, you must prorate the standard meal allowance (figure a reduced amount for each day). You can do so by one of two methods.

• Method 1: You can claim 3/4 of the standard meal allowance.
• Method 2: You can prorate using any method that you consistently apply and that is in accordance with reasonable business practice.

 If it is for a job for with you work as an "employee" receiving a W-2, and they are not reimbursed to you, then you can deduct them as an Unreimbursed Employee Business Form 2106.  It goes on Schedule A Itemized Deductions in the Misc section subject to a 2% of Adjusted Gross Income threshold.  If you don't itemize, then deducting them won't benefit you. 

Where do I enter job-related employee expenses? (Form 2106)

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