Hi @renatto.machado,
If there are Liquid attributes such as {{customer.first_name}} wtihin the collection data, I am afraid it is not quite possible at the moment.
To use collection data, you would run a Query Collection action within the campaign to save the collection data in a profile attribute, and within your campaign emails, you would reference them using Liquid, such as {{customer.title}} or {{customer.text}}. However, it wouldn’t be possible to have attribute references using Liquid within the attributes themselves as it would not render.
You can read more about collections here: https://customer.io/docs/journeys/collections/.
In the meantime, for instances where you often reuse a chunk of content that would be the same for different customers except for their personalised attributes such as name and plan name such as your example, one other option you could consider would be to use Snippets instead: https://customer.io/docs/journeys/snippets/.
Hopefully I’ve not misunderstood your use case and this is helpful to you!