How do you give Minecraft mobs weapons like swords and bows? Is it even possible?
In Hard difficultly there's a chance that when a zombie spawns it'll be one that could pick up items or can change its armor slots (zombies that already spawn with armor or iron tools aren't guaranteed to be this type of zombie).
You'd drop the item or armor on the ground that you want the zombie to equip, and if the given item is better than the current things the zombie has, then the zombie will swap it's pre-existing item or armor for the new one.
For example; if the zombie was already wearing iron armor and was offered diamond armor, then it'll swap the iron for diamond, but if the zombie with iron armor was offered gold armor then the zombie would usually ignore it.
Though it's important to note that if the zombie started out with nothing, then it would accept any item or armor.
However, these types of zombies spawn too rare to be reliable on mass, and I'm unsure if skeletons apply to the mechanics I'm talking about.
There should be in-game commands that could summon a zombie or skeleton with customized held items and armors though, there's one in Java Edition at least, but Bedrock Edition is known for limited commands at the moment, so I can't say for sure.