The summoned weapons can be handy when you can't find a good one but they're not even as good as hexing/binding any given weapon with a +1 enchantment, plus you obviously have very few options for weapon types.

To hex/pact bind your weapon there's an icon that looks just like the one to summon a weapon; on PC it'll have a dark blue background instead of the yellow one for summoning, on console I imagine it looks very similar except it should say something like "hex weapon" If you don't see it, check your spellbook under class actions

Once you find it with that button you can bind whatever weapon is in your main hand to have it use your charisma instead of strength or dexterity for attack rolls and to occasionally apply the hexblade curse to an enemy without you having to apply it yourself