Pardon my ignorance but I couldn't find an option similar to 'Add a Band' for this, searched a lot of topics on the forum too but couldn't find a solution.
I have started a new record label dedicated to metal, want it to be on metal archives. Kindly help.

Label pages are not quite like band pages, in that they are not independent entities listed purely on their own merit. A label must be connected to at least one band or one release (or release version). If the label hasn't released anything to date (or nothing that is listed), it won't show up (at least it shouldn't, orphaned entries can happen).

If the label has a band signed and/or an album (re-)released, it's comparably simply to add it via the edit function for bands/albums. If you cannot do so yourself due to a low rank, you can file a report about it.