My UK visit visa is being delayed, I got a mail from them saying they require more information to process my application. What does this mean? Will I get approval?

This basically means the ECO or Entry Clearance Officer requires more clarification before he/she can reach a decision on your visitor visa application. It is important to provide the required information and/or documents and in some instances it does no harm to resend any previous documents that may be on the list of documents required.

If you are still uncertain, I would recommend using My Legal Services to assist further with your application.