Wood Joint

You mean end to end?

Mortise&Tenon joint with dowl pegs going through the joint sides.

The *best* way is to see what forces are acting on the joint and then use methods which best transfer those forces away from the joint.

If there are no forces, then they can be simply positioned next to each other with no securing needed.

At the other extreme, the joint can be encased in a welded steel splint..

Intermediate methods use a wooden joint, such as a half-lap or mortise and tenon, to give a large surface area for glue to bond the two pieces together. This can be further re-inforced with screws, nails, dowels, biscuits, staples or a combination.

There are other, more complex wooden joints that again seek to maximise glue area and to transfer the load along the grain and not across it.

Or, if "best" is quickest - then you can hammer tie plates (steel plates with tens of small nail-shaped pieces formed on one surface) on either side of the joint - very quick and often used in a roof carcass but this will only transfer forces in the plane of the joint though and won't withstand twisting.