It does. 2018 Form 1040 has the signature line midway through the page. I'll link you to the IRS webpage showing the PDF of the form. You'll see two pages in the PDF; the printed Form 1040 in your return has both "half pages" on one page.
https://www.irs.gov/pub/irs-pdf/f1040.pdf
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***
