Suppose we want to manufacture 10 android tablets. After developing the tablets, Can we install Dolphin Hd in each of the tablets (without any permission) by downloading the app from the android market? Please tell me the procedure to be followed.
It sounds like you want to pre-load the Dolphin Browser on devices you make before you give/sell them to end users. MoboTap (who make the Dolphin Browser) have a Android Device Maker Partner Program that you can sign up for.
You need to register a Google Account on the device to download apps from the Market. If you're going to be selling these devices, the purchasers won't thank you for having to factory reset them to use their own Google Account (which will also remove any apps downloaded on the previous Google account).
However if you're doing something more along the lines of loading apps onto the device and then giving them to employees to use as work devices, then you could register Google Accounts in their name with their work (rather than personal) details and download it from the Market for them.