How do I create automatically incrementing fields for Customer Number and Invoice Numbers?

[SRaymond]

I want a common format for Invoice Numbers based on the date of creation.  Similarly, I want a number to be used for my Customer ID that will increment automatically.

[isabelle]

Hey @SRaymond! 

Thanks for your post in the Seller Community.

I want to know a bit more about this request. Will these custom fields be included when creating an Invoice and a new Customer? Can you provide an example of how this would be used? 

I'll look forward to your reply, as I know we have an automatic Invoice ID that is generated, but you can also customize/edit the ID to make it your own.