Well, you cannot find out anybody’s location just by his phone number. The service provider has an approximate user location because they don’t know which cell tower is the user connected to.
That said, this information is private and there’s no reason the company will share the same with you unless you work in a law enforcement agency.
A few mobile apps can be installed on a mobile phone and share the real-time or lagging location. But for this, you will need to have the cell owner’s permission and agreement before starting to track him/her. I hope you will respect his/her privacy unless it is really something very concerning.