H1B filing - Degree evaluation and expert opinion

Hello friends,
Is degree evaluation report and expert opinion letter mandatory for visa processing ?
If yes what’s the cost and best affordable agency to get it done ?

It depends on the case and situation.
If your H1B is not in the same education major, then you may need them or if the education was not in US. Example. Electronics person trying to work in Computer science role.
It all depends, your attorney would know this better.