When your viewers click the Subscribe button on your channel it means that they want to see more of your content. Your subscribers are critical to your success on YouTube because they tend to spend more time watching your channel than viewers who aren’t subscribed. If they have Notifications turned on, they’ll be alerted when you post something new. They can also view your newly published videos in their Subscriptions feed.
Tips to get viewers click the Subscribe button
Publish quality content. Make sure your videos are original, engaging, and informative.
Establishing an upload schedule helps. If you don't publish videos frequently, viewers won't want to subscribe to your channel.
Optimize your channel by creating a channel trailer to give your audience an idea of your brand, the type of videos you post, and your release schedule.
Optimize your videos' titles, descriptions, thumbnails, and tags to ensure that they reach the right audience.
Organize your videos into sections and playlists and feature them on your homepage.
Record your videos in 1080p or higher. People don’t like to watch videos that have poor audio and video.
Connect with your audience by interacting with them on your videos or live streams and replying or reacting to their comments.
Promote your videos on other platforms.