Hello @JasonG2010 ,
If you're running a true automation series, you can select multiple lists for its trigger. Welcome emails however can only have either all lists or a single, specific list as their sendto options:
Any lists - Your Welcome Email is sent to every new contact that joins any of your contact lists through one of our sign-up tools. This option lets you keep your email content more general for a broader audience.
Send to selected lists - Your Welcome Email is only sent to new contacts that join a specific list of your choosing. This option lets you customize your email content for a specific audience based on their interest.
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