Hi @VijaySrrie,
this isn't a question for the Community, this is a question for a Splunk Architect or a Splunk Professional Service.
Anyway, you can find more infos at https://www.splunk.com/pdfs/technical-briefs/splunk-validated-architectures.pdf
About Indexers, you need at least two Indexers and a Master Node (usually dedicated), the number of Indexers depends on the volume of indexed logs, scheduled searches, users and the presence of Premium Apps as Enterprise Security or ITSI.
About Search Heads, you need at least three Search Heads and a Deployer (also shared with other roles), but the number of SHs depends on the user, scheduled searches and the presence of Premium Apps as Enterprise Security or ITSI.
About hardware reference, you can see at https://docs.splunk.com/Documentation/Splunk/8.2.4/Capacity/Referencehardware and they depends on the usual parameters.
Ciao.
Giuseppe
