Problem
You need to target specific customers that the Audience Builder doesn't have existing filters for.
Solution
Use the custom tag workflow to create a specific list of customers. To send emails to customers based on a specific tag, first create your audience and then set up your campaign. Then, tag the relevant customers to pull them into the audience.
Note: You can only use retention audiences for this workflow. You cannot filter acquisition audiences by customer tag.
Marketing Pro workflows
Create a custom tag type (optional)
Go to Settings > Operations > Tag Types.
Click the Add button and fill out your custom tag details.
Click Save to create your new custom tag.
Set up the audience
Go to the navigation bar and click Marketing.
In the side menu, click Audiences.
Create a new retention audience or edit an existing one.
In the Include section, add the Customer Tag filter to target only customers with your selected tag.

Add any other filters or filter groups needed.
Note: If you include other inclusion criteria within the same filter group as the custom tag, the customer must meet all of those criteria within the filter group to be included in the audience.
When finished, click Continue.
Now, you're ready to create your campaign.
Create the campaign
Go to the navigation bar and click Marketing.
In the side menu, go to Campaigns > Pro Campaigns.
Click Create Campaign > Start from scratch.
Select Email as the category campaign then click Next.
Select the campaign type then click Next.
Enter a campaign name and click Start Building.
In the Audience section, select the audience you created in the previous section.
Finishing setting up the campaign.
When finished, launch the campaign.
Now, when the selected tag is added to a customer profile, the customer will be pulled into the audience reach.
Marketing Pro v2 workflows
Create a custom tag type (optional)
Go to Settings > Operations > Tag Types.
Click the Add button and fill out your custom tag details.
Click Save to create your new custom tag.
Set up the audience
Go to the navigation bar and click Marketing.
In the side menu, go to Audiences > Retention Segments.
Create a new retention audience or edit an existing one.
In the Segment Inclusion Group section, add the Customer Tag filter to target only customers with your selected tag.

Add any other filters needed.
Note: If you include other inclusion criteria within the same filter group as the custom tag, the customer must meet all of those criteria within the filter group to be included in the audience.
When finished, click Continue.
Now, you're ready to create your campaign.
Create the campaign
Go to the navigation bar and click Marketing.
In the side menu, go to Campaigns > Campaign Manager.
Click Create Campaign > Pro Campaign.
Enter a campaign name and click Start Building.
In the Audience section, select the audience you created in the previous section.
Finishing setting up the campaign.
When finished, launch the campaign.
Now, when the selected tag is added to a customer profile, the customer will be pulled into the audience reach.