if i have additional subject in 12th then i can use it while filling government form any if i did it will create any problem in future
In some cases, the government form or entrance exam might allow you to use the marks of your additional subject for calculating your aggregate percentage or meeting eligibility criteria. This is more likely if the additional subject is related to the field you're applying for.
Other times, the form or exam might only consider your marks in the core subjects mentioned in their guidelines. They might not take the additional subject into account.
I hope it helps!