How can we improve WHMCS?

I would like to have an option for clients to download PDF/A compliant invoice as we have problems with authorities be cos I want that whmcs invoice is final and I don't want to send another one thro post office in the paper form. The PDF/A version is suitable for archiving.
I test our invoice generated from whmcs with veraPDF software and it's not compliant with PDF/A at all.
After I get a support team responds to my support request about these issue they see that this would bee useful option in WHMCS and ask me to add new Feature request here.
Now, all we need to do is vote for this option.

Thank you

Kind regards
David