Append custom text to formula

How can I add text at the beginning and end of a formula?

Here is my formula:

Middle(Final;1;2) +“]}”

Which generates this format:

01]}

I’d like to be able to have it look like this:

{[E-CUSTOM TAG:01]}

So basically, I just need to know if it’s possible to add text to the beginning like I have at the end… Thanks!

Subject: Pretty easy

“{[E-CUSTOM TAG:” + @ Middle(Final;1;2) +“]}”