First you need to be subscribed for a PRO plan or PREMIUM plan. You can subscribe via the Pricing Page.

Second you need to have claimed your channel. See here on how to do I claim a channel?

These two preconditions are enough to get a verified channel. Your channel will get a verify badge with a blue checkmark, like in the screenshot below. Here is also an example channel.

This will lead to more trust for users which are in search for channels and services.