I want to create the rule to check syntax error in pull request can you please help to create rules
Which language are we talking about?
Which syntax errors do you want to check?
It’s not recommended to rely on SonarCloud to detect such problems, you better use NodeJS itself for that (e.g. see this article).
Still there is rule
how we activate and deactivate rules can you help me from our dashboard
If I understand correctly, you’re not looking for “creating” rules, but for activating / deactivating them. In that case, I think you’re looking for the Quality Profiles documentation.