I can teach you how to sign your name on a PDF file step by step.
What you need to do:
1.Sign your name on a white paper;
2. Take a photo of your name;
3.Upload the photo onto your PC;
4.White the photo background with Photoshop;
5. Make a digit ID with PDF software;
6.Sign your name on the PDF file via password;
And after that you can sign your name on other PDF files via password too.