Question about steel I BEAM in basement
Sizing the steel beam is only one part of the problem and, as others have said, a SE can do the necessary calcs, or the steel suppliers themselves.
The other part of the problem is supporting the steel beam at its ends. If it's an existing masonry wall, you would need calcs for the size of padstone for bearing. Alternatively, you could build concrete block piers each end, but these would need to be supported on their own footings,which would need to be correctly sized.