Hi Mattis,

This field  Tax Office ID as many others on that screen do not come from standard core App10. Your screen in Core looks like that:

I found that it come from Country specific localization , probably Localization for Turkey , maybe others as well.

There are of course some prerequisites , need to be localization installed and switched on.

You need to have version App10 GET (Global Extension) installed.

Next localizotion should be enabled on Company level:

Next you can use those additional fields for that Company , if Tax Office is defined for country TURKEY:

I don’t know Localization for Turkey , but more details you can find in Country Specific document available in Online Help system.

Best Regards,

Pawel

Hello, 
I think these fields are related not only for localization for Turkey, in French package there  exists corresponding localization as well:

And tax office must belong to the company indicated in the Document Tax Information line .

@Pawel Dworzynski @Adam Bereda this setup was not active so I was not able to chose the tax office ID. now it is easily working via LOV. Thanks!