1. Can I restrict user to edit their post?
I don't think the builtin settings support disallowing a user to edit their own posts. You'll need a custom plugin for that. But why would that be useful in the first place?
3. Some posts goes to under moderation. How to published all post automatically?
Presumably you enabled moderation under Administration center → Spam. Disable it in the same place.
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask here, in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.