You need to provide some more clarity please.
In 2019 we bought.
Who is we? You and your spouse who you file a joint return with?
I began using part
Define "part". Being that this is a 2-family unit (basically a duplex) did you use one of the two units as an office for something? Or only a room or two in one of the units.:
as an office
An office for what? A business that you own? If so, what kind of business? A sole proprietorship or single member LLC that you report on SCH C as a part of your personal tax return? An S-Corp that you report on an 1120-S? A C-Corp that you report on an 1120? A partnership or multi-member LLC that you report on a 1065?
We began renting the other half in 2020
There's that "we" again. Clarity is needed since "I" began using part as an office for something that has not been clearly defined. This matters, because work related expenses for a W-2 job are just flat out not deductible. This includes a home office.
Can we take depreciation for pchs price/ rehap expenses for 2019?
That's a definite NO for the rental half. Depreciation on rental property does not start until the date the property is placed in service. Since the rental until was not placed in service in 2019, absolutely nothing concerning it will be entered anywhere on your 2019 tax return.
You "may" have some SCH A deductions here for 2019. But without more clarification as identified above, it's just not possible to get any more specific.
