..and you don't just take money out of it (unless you truly want to change IRA administrators....even then you would attempt to do a direct transfer first) ....you talk to the people who hold the IRA, and you tell them you want to convert it to a ROTH IRA...and they take care of the conversion, and send you a 1099-R towards the end of January 2019 with all the proper codes on it so that you can enter it properly in the tax software.....and when you enter it in the tax software, you will indicate it was a conversion to a ROTH IRA (if the software behaves similar to what it does now)
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*