How to add the Order ID Prefix?

The payment module I use, Only accept non-repeating Order ID.

Two years ago I deleted all records of orders and recalculate, A few days ago the order number to reach the same number I used two years ago, For this reason, an error message appears repeat orders.

So I have to find a way to add text prefixes in front of ['order_id'], What should I do?

E.g: AA (Order ID Prefix) 26769 (Order ID)
Order ID: AA 26769 (Order ID that can be sent to the payment gateway company website)

You can't. the order id is an auto incrementing number.

Not quite sure of the error you are getting as you've not really said, on the face of it it seems a bit odd.

You could alway alter the table and increasw the starting number for the auto increment value to something new and far above older orders, but I suspect that is not the actual problem here.

By default you can't. But if you are familiar with php coding you can. If no, you can place request for custom job in commercial forum.