The player has round body parts, how can i make a regular part be like this?
If you insert a SpecialMesh into a Part, you can edit the MeshType property to make a brick look like a Head, Torso, Sphere, etc.
For custom shapes, you can use Solid Modeling to edit the Part however you want.
ROBLOX removed beveled bricks a while ago. CSG Plugins or manual CSG can make you beveled bricks, but not like the player's body parts.