PDF Overlay is browser-based software for adding text, images, watermarks, and Bates numbers to PDF documents, operating entirely on the user's device without file uploads. Text customization includes multi-line formatting with bold, italic, underline, and strikethrough options, along with precise positioning and resizing. Built-in fonts are supported, and text can be placed above or behind existing content. Bates numbering allows sequential page labeling with customizable prefixes, counters, and suffixes. Images in PNG or JPEG format can be added via drag-and-drop, with resizing that maintains aspect ratios. Overlays can be applied to specific pages or ranges, with a live preview for accuracy verification. Stamp configurations can be saved and reused across documents. The software preserves links, annotations, and metadata in the output file, ensuring document integrity.