Commodity desktops no longer require IT consultation for acquisition. Your local BestBuy, Canada Computers, Staples and other retailers make it simple to buy a new desktop or laptop computer to fit your budget. Just buy the most powerful (fastest CPU, most memory, largest storage capacity) that you fits your budget.
If your office server uses a domain, be aware that Windows 10 Home Edition cannot participate as a domain member - you need Windows 10 Professional to join a domain. However, in a small office (10 or less computers with a server) you should be able to use a workgroup instead. Windows 10 Home can participate in a workgroup to facilitate sharing resources.