@SatyaraySingh
Convergence angle is a difference between between True North and Grid North, and its value depends on a map projection used in a grid.
If you use WGS 1984, technically this is not a projected coordinate system, but a geographic coordinate system, so your "grid" north with always be True North, and convergence angle is always 0.
The same results would be in WGS 1984 Web Mercator, because the Mercator projection displays straight meridians and Grid North will always be aligned with True North. This would be the case with any cylindrical projection in normal aspect.
With other projected coordinate systems, like UTM or State Plane CRS, True and Grid North might be different, so convergence angle will not always be 0 (depending on the location).
I hope this explains it.