I understand. Actually my PCB don't have wire density. But there is two BGA Type Module, one is at Top and other Bottom Layer. Hence I am not able to place normal Via's as its conflicting with opposite side Module Pads. So I am thinking to to Buried and Blind Via's.
How ever the blind and burried vias are entered in a PCB tool, you'll end up with separate drill files for each via type, one for regular through-vias, one for blind vias to to inner 1, one for blind vias bottom to inner2, one for burried vias inner1 to inner2.
Not all layers ranges can implemented in a specific stack-up, in case of doubt contact the manufacturer before finishing the layout.
Buried vias and blind vias under a component (like a BGA) should be avoided whenever possible, they're expensive to manufacture and more likely to cause connectivity problems. Also, you'll have to add dedicated test points elsewhere on the board because you can't probe the vias anymore, so they aren't saving you a lot of space either.