It seems like without considering third-party apps, the only way to automatically generate .pdf file by nintex workflow 2010 is the "convert document" action. But this action only support converting docx files, which means I have to create a temporary docx file to store data from my form. So an available way is to create a temp docx file then update content controls in it, finally convert it to pdf.
But when I write in content controls problems show up: for plain text control it does not recognize paragraph and just merge my text into one paragraph. in rich text control it just duplicates data twice, even when I write plain text into a rich text control.
So is there a good way to write multi-paragraph data into document files perfectly? or is there other options to convert forms into pdf without third-party apps?