kindly suggest any platform for suitecrm developer learning
The Developer Guide in the new documentation site:
any other site available or not
The resources for SugarCRM up to version 6.5 are also generally applicable.
Then you have the blogs,
and possibly some more that I am forgetting…
which one will you prefer for a beginner
One thing to note is that there will be Development Master Classes taking place in June: https://suitecrm.com/suitecrm-master-classes/