Besides its triggers, anyone allowed can add people to an automation by hand. Switch the automation on first — people can only be added to an automation that's on.
Who
From the automation, Add people → One contact, A smart list, or everyone in the contacts list as filtered now (up to 50,000). From the contacts list, select contacts and add just those. From a contact's page, Add to automation.
People who can't go through it again (the automation's once ever setting) or are already inside are skipped and counted.
When
- Now;
- At a set time (Start at, in the business's time zone);
- In batches over time: a Batch size of people every N Minutes between batches, so a list of 5,000 doesn't all get an email at the same moment; optionally Only on certain days and hours.
Large adds happen in the background (Adding in the background); you can pause, resume or cancel a batch job from the automation.
People added by hand start the automation as if a trigger had started it (Added by hand).