How to add SINV-# into customized invoice print format

Hello guys,
Help needed,
We were using Standing format for Sales invoice, which shows SINV-0001 eg.
Now we created customized invoice format under Customize form. How do we add SINV- # into it?
I added Series into form but only showing “SINV-” without numbers.

Thank you in advance!
ERPnext is great!



create a custom html field, and put this in the content

{{ }}

Thank you!
That works