Tax Year Prior to 2020: Do I need to show a receipt somewhere for job-seeking expenses. Because it did not ask me anywhere to do so. Thank you

No, you don't need to show the receipts, but keep them in case you need to prove the expenses in the future.  

These expenses go on Schedule A Itemized Deductions where they are subject to the 2%-of-adjusted-gross-income limit.   If you have enough expenses, and typically itemize your deductions, it may benefit you.

You may be able to deduct some of your job search costs if you look for a job in the same line of work.  Please see the link below for what you can deduct.

IRS Deductible Job Search Expenses

Where do I enter job-related expenses?

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