Hold Billing is a feature of Salesforce Revenue Cloud that allows businesses to control when an order product is invoiced, based on certain criteria or events. By setting the Hold Billing field to Yes on an order product, the billing process is paused for that order product and all its usage summaries. This means that no invoice lines or invoice documents are generated for the order product until the hold is released. The hold can be released by setting the Hold Billing field to No or null, either manually or automatically through a workflow or trigger. When the hold is released, Salesforce Billing will create an invoice as soon as possible, and include all the invoice lines that were accumulated during the hold period. This ensures that the customer is billed for the full amount of the order product, regardless of the hold duration. For example, if an order product has a monthly billing frequency and a hold billing period of two months, the first invoice after the hold will include three invoice lines: one for the current month and two for the previous months when the hold was active. Reference:
https://help.salesforce.com/s/articleView?id=sf.blng_hold_billing.htm&language=en_US&type=5
https://trailhead.salesforce.com/users/officialblaze/trailmixes/revenue-cloud-get-started-with-billing