How do I generate a single invoice for a subscription with different contract start dates?

There are two ways in which you can generate a single invoice for a subscription with different contract start dates.

Here's how you can do it (assuming that the invoicing rule, charge periodicity, billing frequency, period start and period type for the two subscription products are the same):

1. Using an Align Bill from Date on the subscription with an earlier start date. The Align Bill from Date should be the start date of the subscription product starting later. The idea is to align the billing periods of the two subscriptions. This can be done only in the draft status. The first period till the Align Bill from Date on the first subscription will be billed separately as a partial period.
2. Using a billing offset on the subscription starting earlier to match it with the start date of the subscription starting later. For example: Set the billing offset as 9 days from the start period, that's 2 + 9= 11. This is the bill date of the second subscription starting on the 11th.