I do not have to pay back the grant what if I don't have a idea

What? You are asking if you can get a grant but then not use the grant money for its intended purpose?

Please reread your question and think about whether you could answer it based on what was asked. Then use the Answer options to add a post that explains your situation with enough details so we can try to help.

You must use your grant for the purpose it is requested.
And even to get a grant you will have to do a business plan, and show you have the money to do the other part.

Normally also of course you will have to have real working business before you get the grant.

Next there are not just grants for anything, most grants first are limited, they may cover building costs, or be a building to use. Or they may normally be tax breaks for creating certain jobs. And of course for things like research or more.

If you do a fraud and do not use grant money for its purpose they can arrest you and stand trail with possible prison and fines or more