Bedrock is an unbreakable block that can be found at the lowest levels of the Overworld and highest levels of the Nether. These blocks exist as a barrier to keep players from falling out of the game world. While they can be broken in Creative mode, bedrock is indestructible in most situations. A bedrock block is fireproof and blast resistant and cannot be broken or mined in survival or hardcore mode.
The only place bedrock can be found naturally is at the lowest levels of the Overworld and at the roof of the Nether. You cannot mine it or pick it up without either using commands or switching to the creative game mode. Since you cannot obtain bedrock, you cannot use it for anything. Bedrock comprises the bottom-most layers of the Overworld in a rough pattern, although the top four layers are flat bedrock with some gaps. The last layer is completely flat and mostly inaccessible. In the Nether you can find bedrock at both the roof and bottom of the nether and is generated quite similarly like in the Overworld.
The primary focus of bedrock is to prevent the player from falling off the world, though it can be used creatively for other purposes. You can use bedrock to your advantage when fighting against the wither. There are certain configurations of bedrock that can be used to trap the wither by spawning them below the bedrock. Now the wither can be easily killed and you can use this method to break a ton of blocks or just farm for wither roses.
Bedrock is an indestructible, fireproof, and blast-resistant block that is naturally generated. It is used to keep the player within the game world and has no other natural use, but that doesn't stop players from using their clever minds. From trapping withers to using them for Redstone contraptions, bedrock has been given uses that were never intended.
A. No, obsidian is not stronger and comes second to bedrock.
A. There is absolutely nothing under the bedrock and this zone is called the void.
A. No, there is no method by which you can get bedrock.