Post moved - please read the section descriptions to determine where best to post.
You don't say what version of Archicad you are using - labelling methods have changed in newer versions.
Ideally add your operating system and Archicad version to your signature so you don't have to type it every time.
Answers to your questions can be version and operating system dependent.
In 20 you label on the elevation just the same as you do on the plan.
Select your label and click the element (window).
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11