I assume you converted the property back to personal use on your 2018 tax return. Once you do that, there's nothing to carry forward. Keeping a hard copy of the required documents is something "you" have to do. The below also applies if you converted it back to personal use on your 2019 return.
For the last tax return you reported this rental on SCH E, you need to print out the IRS Form 4562's that apply to that rental property. There are two 4562's for the property and they both print in landscape format. One is titled "Amortization & Depreciation Report" and the other is "Alternative Minimum Tax Depreciation". You also need to print out the IRS Form 8582.
Those forms show your total carry over losses and total depreciation already taken on the property. You will need to keep all of those forms forever. You will need them when one of three things happens in your life.
1) You convert the property back to a rental. (Your depreciation and carry overs continue from where you left off)
2) You sell the property (You'll need to recapture all depreciation taken, and can then take your carry over losses against any gain realized on the sale)
3) Your die (whoever handles your estate will need those forms for your final tax return and/or your estate tax return)
