As far as the K1 goes you will just mark it as final and enter it as it is there.
In order to take your loss you will mark this as a sale of an investment. Enter it in the investment income section of wages and income on your federal return. Click start next to "Stocks, Bonds, Cryptocurrency, Other" (you're the other).
Enter the purchase date of the day that you originally invested in the partnership. For the purchase price you will enter the remaining basis that hasn't been returned to you (you said 10K so that would be what you enter). For sale date enter the final date the partnership was active and for sale price enter zero. That will allow you to take the capital loss for the partnership.
@medgold
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