Hi Leslie,
Maybe this link will help.
Number Formatting
This option is only available in the Commercial Version (Essentials/Business)
Otherwise, if you have the ability to connect to the database table via phpMyAdmin or Navicat (I use Navicat), you can set the auto increment value to 8000 in the table #___hikashop_order on fields order_number and order_invoice_number
Depending on your business rules, they do not have to be the same values.
The formatting is found under table #___hikashop_config on the field order_number_format.
My format is set for SUM-{id size="5"}-{date format="Ymd"} which will result in something like this: SUM-01019-20160511
Hope that helps,
Kelso