spreadsheet

One sheet per property. 

Upper half of the sheet records: 

                  Bought in 2018  ...     2019      2020      2021  2022  .. until 20XX you sold it.

Total Rent  (add up all 12 months below)

Jan.
...
Dec

Total Expense  (add up all the rows below)

Repair

Interest

Insurance

...

End of Expense

Depreciation Basis

Depreciation  (Basis/27.5) 

Profit/Loss  =  Total Rent - Total Expense - Depreciation. 

Then you record all your activities in the later half of the sheet.