Microsoft Project for Office

Here are the main options - https://products.office.com/en-us/project/microsoft-project-licensing

A company licence isn't an option, rather there is Project Online, licensed on a per-user basis.  If you have access to the Office 365 admin center, assuming that's what you have and go to Billing -> Purchase Services, you should see the pricing and option to buy.  Project Online Professional "allows for up to five concurrent installations of the Project desktop application".  Further details are here - https://technet.microsoft.com/en-us/library/project-online-service-description.aspx?f=255&MSPPError=-2147217396.

There may also be the option to buy Project, such as Project Standard 2016 using the traditional Volume Licensing if the company has a suitable arrangement.  Here is a nice https://getlicensingready.com/HandoutStore/Project%20Server%202016%20v16.405.pdf with further details.  There can be complications in this approach if using Office 365 ProPlus for example, further details here:

https://docs.microsoft.com/en-gb/DeployOffice/install-different-office-visio-and-project-versions-on-the-same-computer

https://docs.microsoft.com/en-gb/DeployOffice/use-the-office-deployment-tool-to-install-volume-licensed-editions-of-visio-2016?redirectSourcePath=%252farticle%252f82691bd7-a3d5-47ca-8d8a-0ee43ec2c01f

It's always a good idea to consult a licencing rep or partner to give specific advice per your circumstances, with costings etc.