@Rusiru I don't know how the subscriptions are set up in Office 365, but you can activate a single license. Be aware though, that 1 license will serve 1 user only if you use Pro features. If a "Pro" feature is used in the creation of any report or dashboard, then your end users need to have a Pro license as well. The only caveat to this, would be if the company is doing external reporting only, and using Power BI Embedded in the external facing application, then no additional Pro license is needed, but the pricing model is different based on usage for people interacting with the embedded report.
