The first thing you'll need to do to get started with hooking up Todoist with Zapier and the hundreds of services we work with is adding your Todoist account to Zapier. When creating a Todiost Zap, you will be prompted to add your Account:
You would then be prompted to enter your Todoist Username and Password:
The screen would then ask you to confirm permission settings:
After confirming, your Todoist account would now be linked to your Zapier account. You can now proceed in creating your Zap!