Looks like you want to wait for next year to file for 2018 & 2019 at the same time. In that case, 2018 will have to be mailed and 2019 only can be electronically filed. If you have refund coming to you on the 2018, no problem, refund check will take around 2 months. If you owe instead, late filing penalties will apply. If you have not yet filed for 2018, you can still file electronically till October 15.