Perhaps the most common method of digital communication used by Amateurs and ARES will be FL-Digi and it’s associated programs.
The software is free and available for download at SourceForge:
ARES users may need FL-MSG to send forms, this program is available there too.
This presentation is a good starting point for using FL-Digi with ARES.
NBEMS for Emergency Communications – PowerPoint PPT Presentation
FL-Digi also supports WEFAX
WEFAX (Weatherfax, HF-FAX, Radiofax, and Weather Facsimile) is a slow scan image transmission mode used for weather charts, press images, newspapers, and meteorological reports.
WEFAX was originally developed for satellite but has gained usage in the HF bands.