The invoice content of salon activities can be determined according to the content of specific activities. The following are some possible options:

1. Conference fee: If the salon activities are aimed at a specific meeting or forum, you can consider issuing the invoice content of conference fee.

2. venue rental fee: if the salon activity is held in a certain venue or facility, you can consider issuing an invoice for venue rental fee.

3. service charge: if the salon activities are provided by a service provider, such as etiquette service and catering service, you can consider issuing an invoice for the service charge.

4. Promotion fee: If the salon activity is to promote or promote a product or service, you can consider issuing an invoice for the promotion fee.

5. consulting fee: if the salon activities are aimed at consulting and discussing a specific theme or industry, you can consider issuing an invoice for the consulting fee.

it should be noted that the specific invoice contents should comply with national tax laws and regulations and industry regulations, so as to avoid tax problems caused by violation of relevant regulations. At the same time, before issuing invoices, we should confirm the specific invoice requirements and issuing methods with the event organizers or participants to ensure the accuracy and legality of invoices.