If you are a W-2 employee, you cannot deduct those employee business expenses any longer that used to be itemized deductions subject to reduction of 2% AGI. They ended after being used the last time on the 2017 returns and were no longer available beginning on 2018 returns.
If you are self-employed, you would use the Office in Home Form 8829 to take those deductions for use of your home. The computer usage would be depreciation on the Sch C.