Hi,
For information about Provincial Nomination, you will need to visit the immigration website of each province. You will find information about whether or not they're still accepting applications and other useful information like how to apply.
Do a simple google search with the key words: xyz immigration (xyz will be the name of the province you're interested in).
In the case of Ontario, the application procedure is a little different from the rest. If your CRS is more than or equal to 400, and you satisfy some other requirements (please visit the OINP website for more details), OINP might send a Provincial/Territorial Interest Letter on your CIC. You can only apply for Ontario PNP under Express Entry if you receive this letter on your CIC.
When people mention that they've received a PT from Ontario, they mean they've received this letter and are now able to apply for OINP.