The phloem is always on the outside and the xylem is always on the inside.
To remember which is on the inside and which is on the outside remember X-rays.
X-rays always see inside. The xylem which starts with an X for X-ray sits on the inside of the plant.
This can always be double checked because xylophones (xylem is pronounced zeye-lem) are usually made of wood. The wood is on the inside of the tree so the bark of a tree, which is on the outside must be the phloem.
The old dead phloem cells become the bark.