US tax returns - what is acceptable proof of income

I want to avoid any red flags.


My current employer doesn't give out a monthly payslip. The salary is deposited directly into a joint savings account.


I called the IRS helpline last year and was told that I didn't need any documentation to substantiate the income on my returns, but I have a hard time believing this. Then again, there is no W2 equivalent here (and I read on another thread here that my tax demand note from the IRD may not be accepted as proof of income). Would it be useful to ask my employer for a yearend payroll statement summary? or is my savings passbook good enough to prove income?


The same goes for interest income. Do I just attach a copy of my passbook entries to my return? Also, anyone know what happens if the bank account is a joint account and the other holder is a not a US citizen or resident. Do I have to declare all of the joint account's interest income or half of the interest?


Thanks.