If other colleagues at the same company also need to ship via UPS, does each person need to link their own UPS account?

Currently, yes. Each colleague should go to their own "Company Settings → UPS Integration" and click "Link UPS Account", then log in and authorize using the company's UPS account once. After that, they can use it for shipments and courier shipping. The linked account is the same UPS account, so rates and billing are identical; it's just that each person holds their own authorization credentials. This is a temporary approach: once the system backend adds company-level settings, it will change so the entire company only needs to link once and all colleagues share it. At that point, people who have already linked won't need to do it again. The settings page will indicate whether it's currently "per user" or "company-wide".

V5 desktopShippingPermissions