What is the characteristic of both democracy and capitalism?

That is a good question. Considerable individual choice is one characteristic that both share. In a democratic society the citizen is encouraged to participate (or at least he should be encouraged) and Capitalism is free-ranging and multi-optional with opportunities you can create for yourself.

Democracy and Capitalism are not either/or. But they are not the same thing either. Opportunities in democracy and opportunities in Capitalism should be encouraged in both if both are to succeed.