Files won't sync if they are modified by other program than Nextcloud at Android

I am confused by Android apps:

  1. I would like to modify file ex: test.txt with other app than Nextcloud Notes. How to make sure it is sync after modification?

  2. I would like to copy photo using other program than Nextcloud to folder /storage/emulated/0/Android/media/com.nextcloud.client/nextcloud/[email@domain]/Photos
    Why they are not sync? And how to properly do it?

at Windows 10 it sync immediately