The AcroTeX bundle (LPPL 1.2) contains:
the web package to redefine page layout to web-friendly dimensions;
the exerquiz package for defining on-line exercises and quizzes of various sorts;
the eForms package for support of PDF forms;
the eq2db package for converting an exerquiz quiz for processing by a ASP server-side script.
Note that not all features are supported on Overleaf's preview panel for now; similarly, not all features are supported on all PDF viewers. For best effect, download a copy of the the output PDF, and use Adobe Reader or Acrobat Distiller to open it.