Most conferences, especially the ACM conferences which I write to, suggest that we use title case for titles and headings.
There seems to be no agreement on what is right way to title case. Turns out that there are several styles such as the APA, Chicago, AP, MLA and so on.
The best way seems to be go with the https://capitalizemytitle.com/# site. Check the APA and Chicago style for your title. Use a title where both these styles agree. For instance, I wanted to title “Code Variants and their Retrieval using Knowledge Discover based Approaches”. I figured out that the APA and Chicago version after title casing this statement is, “Code Variants and Their Retrieval Using Knowledge Discover Based Approaches”. So, I went with it.