I filled up online, printed, wrote by hand what I couldn’t do online, scanned and uploaded online

thank you

I also used to have the same question before I filed i-130 online for my parents on June, I was told there are two options 1, if you have a writing pad you can use the pad to sign the PDF or 2, write your (petitioners) full name on it. I've chosen the second one and don't have any issues till now. The cases are now "being actively reviewing". I'm just sharing my experience and I hope others can add.