Finalize the API in PHP to synchronize the application and Bitrix24

It is necessary to finalize the API documentation in PHP. The API is hosted on the server, access is provided by ladies.
The API transfers orders from the mobile application to Bitrix24 (boxed version).
We also need to improve the profile management and show how the functionality works. That is, we delete the profile in the application - it is deleted in Bitrix24.

If you have any additional questions about the task - write, I will try to answer everything.

There is a more detailed description of the problem here: https://buildin.ai/whitetigersoft/share/5ebd5aa1-3eb6-4155-aa88-65e806b3f001?code=M63DY8

Offer your price in the message.
I also ask you to estimate the timing.