A signature you can drop anywhere
The useful thing about a signature as a transparent PNG is that it sits over anything — a PDF, a Word doc, an image — with no white box around it. This tool trims tight to the ink and exports exactly that. Draw it with a mouse (a phone or tablet with a finger or stylus gives a far more natural line), or type your name in a script font when a formal mark is all that's needed.
The natural next step is Sign PDF: make the signature here, then drop the PNG onto the document and position it — both tools run entirely in your browser, so neither your signature nor the contract is ever uploaded. That privacy matters more here than almost anywhere, since a signature image is a sensitive thing to hand a stranger's server.