Prior to Tax Year 2019 and the passage of the Tax Cuts and Jobs Act (TCJA), wage earners who itemized deductions could claim various miscellaneous deductions, including a home office if one was required by their employer and the office was used solely and exclusively for business. The TCJA eliminated the ability to claim all miscellaneous deductions, including a home office.
Some states, such as California, still allow wage earners to claim a home office required by their employer and used solely and exclusively for business. The space doesn't have to be a separate room but it can't be a space used for other things. Be sure to check with your tax preparer to see if your state allows a home office deduction and, if so, what requirements must be met in order to claim the deduction.