Convert pdf to tex
A browser can't do this one — here is what it can do.
Desktop app only
Nothing that runs in a tab can write tex from pdf. This pair is waiting on the desktop build, which hands the job to the real command-line tools.
Browse what does workAbout PDF
Portable Document Format
Adobe's fixed-layout document format from 1993, an ISO standard (ISO 32000) since 2008. It embeds fonts and images so each page looks the same on every device. Use it for documents you want to send, print or archive without the layout shifting.
About TEX
LaTeX source
Source for TeX, Donald Knuth's typesetting system from 1978, usually written with LaTeX macros. Compiling the file produces the formatted document. Use it for papers, theses and math-heavy writing, especially submissions to journals and arXiv.