Most modeling tools lack out-of-the-box arc42 support, you have to create your desired arc42 (sub-)structures by yourself.
arc42 does provide an empty arc42-structured model for Sparx Enterprise Architect®, although not very elaborated.
We advice to restrict the use of modeling tools to the pure graphical part of architecture documentation, leave text and tables to other tools that are more suited for these kinds of information. In this case, create the following arc42-sections in your modeling tool:
- Context view
- Building block view
- Runtime view
- Deployment view
- Crosscutting concepts