>>Can you please advise on which taxi or cab company to use.<<
You DO realize that the Buffalo Niagara Int’l Airport is approx. 107 miles / 171 km from Toronto, a drive of about 2½ hours without traffic delays. You will need to factor in additional time to clear Canada Customs at the border
A taxi / Uber / Lyft will very expensive, and the driver will require his / her own passport.
Have a look at Greyhound’s NeOn service