How to write a custom activity for a business process for a boxed Bitrix24?

Question

Bitrix24

Does anyone know of a course, or where can I find up-to-date documentation on this subject?

Answer 1

There is an article that has not lost its relevance with a recording of a webinar by Malyshyn and Kalinin with an analysis of the creation of activities.
From myself I can add: look at modern activities (bitrix/activities/bitrix/crmsetshipmentfield) and simple ones (bitrix/activities/bitrix/logactivity) - they will help you figure it out faster.