Most likely, you report it as a business profit on Schedule C. Alternatively, you report it as a capital gain on form 8949 and Schedule D.
For more info, in making that determination, see an older similar question at: https://ttlc.intuit.com/questions/3399983-tax-issues-regarding-flipping-of-a-house
And references at:
https://www.hrblock.com/tax-center/income/real-estate/flipping-houses-taxes/
https://fitsmallbusiness.com/taxes-on-flipping-houses/ https://www.lendinghome.com/blog/how-to-maximize-house-flipping-tax-benefits/
If you treat it as an investment, you expenses fall into the categories:
1. cost of improvements. These are added to you cost basis.
2. Carrying costs, e,g, insurance and utilities. These are not deductible.
3. Closing costs, e.g commission. These adjust you basis and are entered separately in TurboTax
