Hi @borismh
Below is the workflow for the same :-
MainPratik.xaml (19.4 KB)

To find the current Year :-
Int32 currentYear = DateTime.Now.Year
Condition to Check If Leap Year or Not :-
currentYear Mod 4=0
Dictionary to Store Total Days of Month in Leap Year :-
Dictionary(Of String, Int32) dicOfMonth = New Dictionary(Of String, Int32) From {{"January",31},{"Febuary",29},{"March",31},{"April",30},{"May",31},{"June",30},{"July",31},{"August",31},{"September",30},{"October",31},{"November",30},{"December",31}}
Dictionary to Store Total Days of Month in Non Leap Year :-
Dictionary(Of String, Int32) dicOfMonth = New Dictionary(Of String, Int32) From {{"January",31},{"Febuary",28},{"March",31},{"April",30},{"May",31},{"June",30},{"July",31},{"August",31},{"September",30},{"October",31},{"November",30},{"December",31}}
To Find Current Month :-
String currentMonth = DateTime.Now.ToString("MMMM")
To Find Value using Key i.e., For which month how many days are der :-
Int32 daysInCurrentMonth = dicOfMonth.First(Function(x)x.Key.ToString.Equals(currentMonth.ToString)).Value
Formatting Last Date of Current Month :-
String lastDateOfCurrentMonth = daysInCurrentMonth.ToString+"/"+DateTime.Now.Month.ToString+"/"+currentYear.ToString
Again Within IF Condition to check weather todays date is last date of the current month :-
DateTime.Now.ToString("dd/M/yyyy").Equals(lastDateOfCurrentMonth)
Depending on Above Condition True Or False perform the Operation you want :-
Mark as solution and like it if this helps you 
Happy Automation 
Best Regards
Er Pratik Wavhal 
