If I use MonthCalendar in a program that I am working on for personal/medical use, is there a way to program that if the user click a date a new form will appear filling in the date automatically and closes the form with the MonthCalendar? And then when you finish entering the data you want to enter, save the data to file, close the 2nd form and return to the 1st form?

Yes you should be able to program that functionality.

There are multiple ways to solve this, here is how I would do it:
Create 2 global variables called:
Dim MonthCalForm as Form1
Dim DayInformation as Form2

When I open the Month Calander form, I will set MonthCalForm = new Form1 and call MonthCalForm.Show()

When I select a date (there is probably a DateSelected handler), (I would make a Sub New for Form2 with Date as a parameter to streamline the form configuring itself)

DayInformation = New Form2(Date)
DayInformation.Show()
MonthCalForm.Hide()
DayInfromation.Focus()

When I click Save or Exit the DayInformation form, I would call MonthCalForm.Show() and possibly a public update function to grab updated information MonthCalForm.Update()

That is how I would do it, of course I am just some punk kid
Sean C