You ned to describe your business to get a decent answer

The answer is Social Media.
Social media is an ocean of audience who are looking for your fitness services.
How to attract them?

• Create a page
• Post some catchy pictures and videos to engage them.
• After gaining their trust, start doing the real business.
• Don’t forget to communicate with them through comments, messages and going live.

Points to remember,

• Don’t copy the content from others. Be original, be unique.
• Don’t use click baits too much.
• Be punctual and down to earth. Being rude repels audience.
• Be active for most of the time to monitor the activities on your post. Try to reply to the private messages quickly. Making them wait for a while will turn them off.

Some of the topmost social media platforms to outgrow your business are Instagram, Facebook, Youtube, Pinterest, Quora, and Twitter.