Adding a New Customer and Editing an Existing One
Adding a New Customer
Go to Sales → Customers → New Customer (+)
Select the Customer Type: either Consumer or Company
Enter the appropriate identifier based on the type:
Business ID (Y-tunnus) for a company
Personal ID (henkilötunnus) for a consumer
Fill in the remaining required customer details
Click Save
Editing an Existing Customer
Go to Sales → Customers
Click the pencil icon next to the customer you wish to edit
Update the Business ID or Personal ID, along with any other necessary information