I wanna learn SEO so I can get work from online marketplace. How much time I would have to spend to learn it well??
This is not answering you question but it is a interesting read about the SEO topic.
SEO is a full fledged career option and it needs so much time and experience to learn about it.
However, you can enrol into some digital marketing courses and earn some certificates from there.
SEO is the endless strategy where things are keep on updating but you can learn basic SEO.