Q. Do we need to include anything on the house on our 2019 taxes since we purchased the house in 2019? We really didn't have any expenses in 2019 other than mortgage interest and property taxes.
Assuming this is an investment, and not a flip business (discussed in the other replies), you can deduct the real estate taxes on Schedule A (itemized deductions) for 2019 or add it to the cost basis when sold (special procedures required). You may not deduct mortgage interest* on Schedule A (it is neither your primary or 2nd home, it's investment property) but you can add the interest to your cost basis.
Real estate (property) tax may be deducted on schedule A, under taxes, without regard to the old 2% rule.
Alternatively, taxpayers can elect to capitalize (add it to your cost basis) the carrying costs of unimproved and nonproductive real property, real property under development or construction and personal property before its installation or use or sale (Regs. Sec. 1.266-1(b)(1)). The election is made with the tax return by its due date, including extension, by attaching a statement. You cannot wait until you sell the property, but must make that election each year (2019 in your case). Attach the statement to the return and write “Filed pursuant to section 301.9100-2” on the statement. You may add the carrying costs, incurred in the year of sale (2020), directly to your cost basis.
The carrying costs (repairs, insurance, utilities, etc of investment property are not deductible, staring with tax year 2018. It's not clear whether those expenses can still be capitalized. Reference:
https://www.picpa.org/articles/cpa-now-blog/cpa-now/2020/02/19/consider-capitalizing-for-tax-breaks-...
*Mortgage interest is deductible, on Schedule A, as investment interest, but only to the extent of other investment income (unlikely for most people) and not subject to the old 2% of AGI rule, but can be capitalized, as described above
