Lets I have four separate microservice application which I want to deploy in K8's clusters. These applications interact with each other a lot. So is it recommended to have them in the same pod or individual pod for each microservcie
You should have one pod for each microservices. You should be able to build and deploy each microservice independently. if you put all in one pod then it is not called microservice rather it would be a monolothic application.
Different pods. You only combine containers into one pod when they are very specifically for the same thing. Generally this means sidecars supporting the primary container in the pod for things like metrics, logging, or networking.