I would recommend the following courses :
Udemy : You can try the very basic level course from Udemy. You will learn from the very basics to advance level.
Intellipaat : You can try an ML course from Intellipaat. They have 1:1 sessions for doubt clearing. Numerous assignments and projects to make you an expert in Machine Learning.
Coursera : One of best courses offered by Stanford university, you can opt for this course from their website.
If you want some free courses, just google it and you will find plenty of free courses to begin with. But if you really want to master ML then invest in good course for better support and knowledge.
If you want a certificate then go with Udemy or Coursera or Intellipaat. You can get free certificate from Coursera through financial aids.
If you want to become an expert in Machine Learning, checkout this Machine Learning Certification Course offered by Intellipaat.