Electronic signatures without uploading your documents

Most people who need to sign a PDF end up uploading it to a stranger's server. In the majority of cases that is unnecessary — what they actually need is a small transparent image.

Transparency is the whole trick

A signature saved as JPEG carries a white rectangle with it, which sits on top of the document text and looks pasted on. PNG and WebP have an alpha channel, so only the ink is drawn. If a tool offers JPEG only, it cannot produce a usable signature.

Draw beats type for authenticity

A typed script font is fine for an email footer. For anything that will be compared to a wet signature, draw it — a trackpad or a phone screen with a finger produces natural stroke variation that a font cannot.

Ink colour matters more than you think

Pure black reads as printed. A very dark blue or near-black grey looks like a pen on paper and scans more convincingly.

Legality is separate from the image

An image is not, by itself, an e-signature in the legal sense. Depending on your jurisdiction and the document type, you may need an audit trail or a qualified certificate. Producing the graphic locally does not change those requirements — it just avoids handing your contract to a third party while you do it.