The number of their colour, sockets and relations can be changed using several items
The Orb of jeweller - allows you to Path of exile currency re-draw the amount of sockets within an object, raising or reducing it. You won't be able to use that item, if the amount of slots would be the maximum for a given item. Chromatic Orb - allows you to change the colors of the sockets in the merchandise. Orb of Fusing - allows you eliminating them or adding new ones. Vaal Orb - an item which allows you to modify an item randomly and apply the Corrupted parameter.
It's well worth recalling that it makes no sense to waste the above mentioned items on modifying low-level equipment. A much better idea is just to discover another, even worse in terms of parameters, thing which is going to have the sockets we need, and leave the things to be altered for later, to change in better gear.
Path of Exile - the very first hours of this match
How to manage this scenario and where to go to smoothly enter the game world? The start and the full length of the game will probably be identical for all character types, differences will look in terms of equipment and skill stones. Should you play, as an instance, a personality in the Witch class, you'll come across that the best-performing items for POE currency buy that course - like Driftwood Wand, that is your first weapon or Fireball, the first skill you can obtain.