Here you can learn how to join fiverr for selling services as freelancer.

You should check What is Freelancing beginner freelance guide
First need to go on fiverr Website where can join it as service seller.

Click on Join Button.

Enter  your valid email address and click on Continue Button.

Choose a Unique Username and strong password and click on Join Button. Your username is 15 characters long and can’t contain special characters. Prefer using your real name as a Fiverr Username.

Now, you are a registered Fiverr  seller.  Fiverr sends you a confirmation email at your provided email address. Open your email and Click on Activate Your Account  and you are all done with the Fiverr sign up.