Small business accounting

What are Invoice numbers?

Last updated
March 3, 2025

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What are Invoice numbers?

An invoice number is a unique number that is assigned to each invoice. This number is one of the most important elements of every invoice. Its role is to identify transactions, so it needs to be unique. Invoice number can contain only numbers or letters and numbers. It may contain date of issue, name of project or task.

<p>An invoice number is a unique number that is assigned to each invoice. This number is one of the most important elements of every invoice. Its role is to identify transactions, so it needs to be unique. Invoice number can contain only numbers or letters and numbers. It may contain date of issue, name of project or task.</p>

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