Actual proof of income is a payslip, which includes Form 16 provided to the employee by the employer. A payslip alone is not strong evidence of proof of income. An appointment letter is never proof of income. A bank statement indicating the credit of salary in your account is considered as evidence of income under the Indian Evidence Act. However, I would still suggest that Form 16 is a far better and the only strong evidence of income.
If You Have Other Sources of Income Apart from a Salary
CASE 1:
If, apart from your job, you have other sources of income, then under the Income Tax Act of 1961, the clubbing of income is mandatory to determine taxable income. If you file income tax separately under a self-assessment scheme or have it filed by a CA/CS/CWA on your behalf, meaning that your employer does not perform tax deduction at source, then a form provided by the Income Tax Authority, ratified by the seal of CA/CS/CWA, can be considered as your source of income.
CASE 2:
If your employer conducts tax deduction at source, then Form 16 is the best proof of income. If you file a return of income tax for tax deducted by the employer to avoid double taxation, then such a return form along with tax filing documents should be considered as an income certificate. The procedure will be similar to that of Case 1.
Examples of Other Sources of Income
1. Income under the head, House Rent or property rent.
2. Income from Business or profession.
3. Income from other sources.
Hope your problem is solved.
Thanks & Regards,
Sovik B