US Immigration from Singapore

We're still a few months away from needing to send in the ROC package. In the spirit of avoiding last minute work, I want to print out a few past bank statements and going forward, print them out as soon as they come in. We use our joint bank account to pay rent, some school fees, and going forward, utilities as well as Internet bills. I noticed that for our rent checks, the statement itself doesn't say where the money is going to, just a check number. Do you annotate your bank statement to show what various substantial transactions are for? Is that important/necessary/helpful? Or do you just let the statements speak for themselves, showing that there's regular and substantial movement within the account?

And if you do annotate your statements, what's the best way of doing so? Post it labels? Write in a differently colored ink pen?

Thanks in advance,