Quite unfortunately it is not possible for the State tax return to be e-filed. Instead, it has to be physically mailed.
Complete mailing instructions can be found on the first few pages of your return's PDF file.
How can I download my PDF file? To download your tax returns prepared by Sprintax, please navigate towards the upper right corner of your screen and click on your profile icon. Afterwards, please click on the 'Download Your Forms' option: