If you need to issue an invoice for mobile phone maintenance fees, you can choose the following two product codes for invoicing:

1. Service product code: For example, 50000103-005-006-001 is " "Mobile phone repair" service product code. When invoicing, you can select this code for invoicing.

2. Spare parts product code: If spare parts need to be replaced during mobile phone repair, such as screen or battery replacement, you can select the corresponding spare parts product code for invoicing. Different spare parts have different product codes, so you need to choose according to the specific situation.