Why cant I invoice cis customer through app ?

Hello @contact59,

At this time, the CIS and associated features are available only in the web-version.  I'm adding an article you can read to learn more about CIS in QuickBooks.

I'll be also creating a feedback ticket to be submitted directly to our product developers to let them know about your request. You can always visit our blog for future updates.

If you have any other questions, let me know in the comments. Always around ready to help.