We are planning to building new F5 instances in Azure. Plan is to provision 2 F5 VE instances in Azure. Please let me will it be a best approach to go with Active - Active F5 HA or Active - Passive F5 HA in cloud.
It is difficult to say what is the best option - there are pros and cons of each, and you decide based on your own requirements. This is the sort of thing that we in F5 Professional Services do regularly - discuss the options, explain the pros and cons, and maybe perform a Proof of Concept or suchlike to allow you to see the difference.