Pay Roll and Date format problem in software

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I am preparing an Auto Pay Roll software including Pay Fixation/ Pension & Leave Salary Calculation/ Budget for Pay related/ Monthly Salary/ for Central Govt. in Visual Basic 6 & database format is MDB (Access).

1. While testing the out put value of Date shows like 7/27/2018 but it should be 27/7/2018 and sometimes the calculation result goes wrong due to this date format.
How to show in Code dates to be taken from the database and send the result (dates) to the database.
My code
Dim DtBox as date
DtBox = Format(Text1.Text, "dd-MMM-yyyy")
(Input Codes and Output codes for Date)

2. After finishing this software in VB6, will it work in all Windows platforms? (I am testing only in Win7,WinXP).

3. Is it possible to convert VB6 codes (which I have written 850 pages and 70 forms) to present VB2017? (I know only VB6 and all MS office). Before distributing, should I buy the Original software (As VB6 was abandoned, so I Installed & learned it and preparing this software)?

4. Those who use my software, if they didn't install Access, will it function in their computer?

5. Instead of Access as back-end database, Is any easy other format Database available? (Easy to learn?)

6. Which Govt Agency, will support me (to bundle my software in their dept's Original Soft like VB6 or VB2017?

As this 2 years work still incomplete due to Testing. Please guide me.