For the individual return i see Installment Agreement request form 3567 which shows sections for the amt they are paying and the amt per month.  Note that the Installment Agreement must be mailed and is subject to approval.  If you've already efiled for balance due via electronic funds withdrawal, then i guess it would be possible that the full balance may be reflected on the voucher, but if i were you, i would confirm with the CA government instructions and/or their department of revenue on the best way to proceed.