If you have a list of customers you want to target in a campaign, there are two approaches you can take. For instance, if you have an Excel sheet containing email addresses that you wish to include in an email campaign, you can target them using one of the following methods:
Creating a custom customer attribute
When importing a list of customers and, for example, their emails, which are also Soft or Hard IDs for your project, you can identify this import by adding an extra column that contains a custom customer attribute. First, define this customer attribute in the Data Manager before the import, naming it something that quickly identifies the import. Then, add the same customer attribute as a column in the Excel sheet you are about to import and fill it with some values. It can be a boolean or string, for example, but it depends on your settings in the data manager.
Once uploaded, this custom attribute will be added to the customer profiles identified by your Excel sheet's IDs (such as email addresses). You can later use this custom customer attribute with its value in scenario conditions or customer filters to identify the newly imported list of customers. This method is recommended as the best way to identify a specific list of customers from an Excel sheet.
Optional: Using the IN filter in customer filters
If your customer list is small (e.g., in the tens), you can also use the IN filter in the customer filter, where you copy the list of IDs you intend to target in the campaign inside the IN filter values for the selected ID. This is the quickest and easiest solution; however, it is not recommended for more extensive lists of customer IDs or when you plan to target the same group repeatedly. Creating a custom attribute to identify these customers and their IDs is always the better option.