> ## Documentation Index
> Fetch the complete documentation index at: https://www.plain.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# addCustomerToTenants

> Adds a customer to one or more tenants. The customer can be identified by their Plain ID, external ID, or email address.
If the customer is already a member of a given tenant the operation is a no-op for that tenant.
Requires the `customer:edit` and `customerTenantMembership:create` permissions.