The Caretaker’s Workshop is a key part of helping you and your party get significantly stronger in Dragon Age The Veilguard. You will unlock it at shop rank 1 which provides you with the most basic upgrades to your weapon, armor, and belts.
However, once you start increasing its’ ranks you will gain access to more powerful upgrades along with Companion Enchantments which unlock at rank 5. However, to rank up the Workshop you will need to get Caretaker Reputation or Caretake Power which will then unlock more upgrades for you as a result.
Here is a guide that goes over some of the best ways of acquiring Caretaker Reputation points to upgrade Workshop rank in the RPG.
How to gain Caretaker Reputation points to increase Workshop rank in Dragon Age The Veilguard

Here are some of the best ways of improving Caretaker Workshop ranks in Dragon Age The Veilguard:
1) Completing story quests
The most basic way of getting more Catretaker Reputation points is to complete the story missions and quests in the game. Most of them will reward you with some points, while individually they are not as effective, they start racking up once you start reaching the later stages of the game.
You will need 250 points for shop rank 2, then 750 for rank 3, 1250 points for rank 4, and so on.
2) Collecting Mementos
Mementos are by far the best and most effective way of farming Caretaker Reputation points in Dragon Age The Veilguard. These items are found all throughout Thedas and in general, they will offer 50 Reputation points.
Along with Mementos you will at times find similar valuable objects which will reward you with 200 Caretaker Power, however, they are a bit rarer to come across.
Additionally, you will also be able to purchase Mementos from vendors that are located in the marker. You will need Etheric Remnants to buy them, making that a costly option. Mementos are sold by Faction vendors as well, however, you will need somewhere between 150-500 gold per item.