> For the complete documentation index, see [llms.txt](https://docs.cymbal.co/help/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cymbal.co/help/segmentation/attributes.md).
# Attributes
This page describes how to tag contacts with unique identifiers to use for transactional, promotional, or marketing purposes.
Attributes are a way to assign custom data to a contact that is not included as a default attribute.
For example, Cymbal natively supports attributes such as phone number, email address, tags, and genres. However, if you’d like to store a membership ID or another custom data point for a contact, you can do so by creating a custom attribute.
Once created, custom attributes can be used for audience segmentation, personalization, and targeted marketing or promotional campaigns.
### How to create an Attribute:
1. Select [Audience](https://manager.cymbal.co/audience)
2. Click *Attributes* in the top right corner
3. You can see past *Attributes* you have created or create a new one
4. When creating a new *Attribute* you can choose whether it will be a *text* or *number* value
5. You will see your new *Attribute* appear in the selection modal
6. To use this *Attribute*, you’ll need to upload a contact CSV that includes the data you want to assign to each contact
7. Once the file upload is complete, you can use the *Attribute* to filter contacts, target specific audiences, or dynamically personalize your messages.
