Active Externalism is the idea that we can use our environment to extend our cognitive processes. One example is to use a calculator to perform a calculation. Another is to use Trilium,  Obsidian or a notepad to store information related to your memory. 

The paper by Andy Clark starts with Where does the mind stop and the rest of the world begin? It dives a lot more in the implications and definitions of the border between mind, body and environment. For me however, Active Externalism is a tool I use to achieve my goals.