You asked
Can I use adapted lenses on the olympus pen e pl8?
The site doesn't cover adapters, so I can't tell you how a lens from another mount would work on the PEN E-PL8. What I can tell you is that it takes Micro Four Thirds lenses, and every lens on its catalogue page fits it natively, with the full-frame equivalent focal lengths listed beside each one.
If you want a simple, sharp everyday prime, I'd start with the Olympus M.Zuiko 25mm f/1.8, which frames like a 50mm on full frame. For a wider view, the Olympus M.Zuiko 12mm f/2 is a small, good-value pick.
For the wider picture on mounts and lens choice, the Micro Four Thirds guide is the place to look.
Written by Claude from this site's pages.