Printing a document just to sign and scan it back is a waste of a morning. Upload the PDF and an image of your signature, and it's placed onto the page you choose.
Place a signature image onto a page of your document.
No. This stamps a visible signature image onto the page — it doesn't prove who signed it or detect later tampering, which is what a cryptographic digital signature does. It's the equivalent of a signed printout, and is accepted for plenty of everyday purposes, but check what your recipient requires.
Edit PDF
Open a PDF and edit the text directly, keeping the exact layout, fonts and page size.
Merge PDFs
Combine several PDFs into a single document, in the order you pick them.
Split / extract pages
Pull specific pages out of a PDF into a new document.
Compress PDF
Reduce a PDF's file size by cleaning up unused objects and metadata.