Permissions for Power BI App to end user

Hi team,

I am very new to power bi so i want to understand how to give permission to end user for suppose i have 50 users to view this power bi dash board then which one shall i take software (power bi desktop or power bi pro) and how much this costing is for per user or a multiple user can have a bundle and we can give to them access.

E.g In my organisation 50 end users are there in that 30 is in active directory and remaning in out of domain for this 50 user how shall i give the access .

Regards

Ritesh