Everyone can enter the morph realm via your spellbook. It looks just the same as the normal world. It has the same bosses/npcs. Everything behaves the same way except your stats. If you're a normal player in bandos armor doing bandos GWD and you see that it's crowded, you can enter the morph realm and hope that there are no morphs there. Keep in mind that a normal player will have 20% reduced stats. The stats that are reduced are: Attack, Strength, Defence, Ranging and Magic. You can always use potions to get them up again but not to the same level as in the normal world.