If you are a rookie and are looking to learn how to sing online, it can be hard to know which type of singing lessons is best for you. However, there are a few different options out there, so it is worth checking out what is available and what you think is best for you.
One of the first things you may want to look at is a free course. These are typically quite good in teaching you basic things such as posture and breathing, but they are not always tailored to your particular situation. Many of the free courses will only offer you basic lessons that will give you an idea of the basics and a general idea of improving your singing voice over time.
A good option for beginners is an online paid course to learn singing. They can vary a lot from course to course, but many have the same basics. Some of them even have many audio clips to practice your singing while you work at the course.