Literally, de facturación means of billing or related to billing.
So:
Together, periodo de facturación means billing period or billing cycle.
This is a very common Spanish structure:
Examples:
Facturación comes from facturar, which means to bill or to invoice.
So facturación refers to:
In business, subscription, banking, and telecom contexts, facturación is very common.
Spanish often uses the present tense to talk about a scheduled or expected future event, especially when there is a clear time expression like mañana.
So:
This sounds natural in both Spanish and English.
Spanish also allows:
That version is more explicitly future, but termina mañana is completely normal and very common.
Because mañana can function as a time adverb, meaning tomorrow.
Spanish often uses time words directly:
So you simply say:
No extra preposition is needed.
Yes. Spanish word order is flexible.
You can say:
Both are correct.
The first version is more neutral and straightforward. The second puts more emphasis on mañana.
It is neutral and standard.
It would sound natural in:
It is neither overly formal nor casual, which makes it very useful for everyday business Spanish.