Add button in Calendar interface

Hi.
This is my first topic around here.
Does NextCloud provide ways to add components (buttons, text input fields, selection fields, etc…) to apps?
I need to add a button on the Calendar that makes an external request and gets a value and then fills in the description.
Attached prototype.

Thanks!

Captura de Tela 2021-12-15 às 10.51.43

Maybe using JSLoader (https://apps.nextcloud.com/apps/jsloader) could be a possibility to manipulate the DOM?

2 Likes

Thanks for your response.