How do nonprofits currently mobilize their constituents for advocacy campaigns?

I'm Patrick from the Cicero team. We built a web tool called District Match that lets you upload spreadsheets of addresses and match them to legislative districts & representative contact info in bulk for advocacy campaigns. I was wondering what tools and workflows nonprofits currently use to mobilize their constituents for advocacy campaigns - i.e. to call, write, and email the right elected officials based on which districts they live in?