Form 8606 is always required to report a Roth conversion. Generally this form is included with your tax return for the year in which the distribution from the traditional IRA is made. Unless you have already made the distribution from the traditional IRA before the end of 2017 (after early November), "I am moving all of the funds in a traditional IRA to my Roth IRA via a Roth Conversion" suggests that you will be doing this in 2018, and the 2018 distribution from the traditional IRA and it's conversion to Roth will be reportable on a 2018 Form 8606. If you are not otherwise required to file a tax return, Form 8606 can be filed stand-alone.
To avoid an underpayment penalty, you may also need to make an estimated tax payment for the quarter in which you make the distribution from the traditional IRA. Whether or not you need to make the estimated tax payment will depend on whether or not you will otherwise meet one of the safe harbors for avoiding the underpayment penalty.
https://www.irs.gov/taxtopics/tc306
Instructions for Form 8606: https://www.irs.gov/pub/irs-pdf/i8606.pdf
