The "Conversion and merge tools" extensions simplify the file conversion process, eliminating the need to install individual native programs for each type of conversion. These extensions either use a sandbox converter or employ an online service to convert and merge files. For instance, the "PDF Combine - Convert and Merge" extension allows users to convert a single document or image file format to a PDF document, as well as convert and merge multiple files of various formats into a single PDF document. Users can add multiple files and arrange their order using the extension's user interface before requesting conversion. It is worth noting that any file format can be merged into a single PDF file, allowing users to attach images to their PDF documents. The user can request a new conversion by dragging and dropping the PDF file and image file into the view and clicking the "convert" button. The extension places the resulting PDF file in the default download directory of your browser.