It’s been awhile since I’ve looked at the rules but you can see the most up to date info and processes on the IRCC website:
https://www.canada.ca/en/immigration...-children.html
One thing they’ll want to consider is whether she is going to apply from within Canada, or outside Canada. The benefit of the former is that if she is (legally) in Canada when she applies, she can remain in Canada (ie even after her six month visitor status expires) while she awaits approval (it is currently taking 16 months).
As for working, she would normally need a work permit in order to work while she’s in Canada. However, if she’s working remotely in Canada for a US employer and is being paid by that US employer, I’m not sure if she needs a work permit (something worth confirming to be sure).