Custom fields "Invoice Fields"

I have a question about “Invoice Fields”
I set a new Field Label “LZeitraum”
If I create a new Invoice I can see this Label “LZeitraum” on top.
I changed code in custom invoice design and set variable $LZeitraum but nothing changed.
I tried to set variable as $LZeitraumValue but it did not help.
Which variable should I use in code?

Thanks

Custom fields should automatically be added to the invoice.

It isn’t currently possible to manually add them in a custom design.

What a pity!

Is it currently possible to manually add “invoice custom fields” in a custom design?
If yes, What’s the name of variable? I didn’t find their in database, only the labels name.

Thanks

The variable is $customTextValue1

It works!

Thank you very match

Great to hear!

The variable is $customTextValue1

How to get the label associated?

$account.customInvoiceTextLabel1