User Interfaces (UI) and Heads-up Displays (HUD) combined are responsible for communicating information about the game like your health, abilities, status effects, and the list goes on. In an MMO like Final Fantasy XIV, the sheer quantity of information the UI throws at you can be disorienting, and finding specific information in a pinch can be a stressful ordeal.
Fortunately, FFXIV provides a robust set of tools to rearrange and customize your UI, allowing you to personalize your setup to fit your needs. This guide will introduce you to the various UI customization options and leave you with some advice to get you thinking about ways you can perfect your own layout.
Players looking for tips on setting up their hotbars and keybinds can find in-depth advice in our dedicated guides on setting up hotbars for keyboard and controller players.
Customizing your UI
The main method of editing your UI is the HUD editor accessed by entering the System menu (Escape by default, or by clicking the XIV button on your main menu bar) and selecting HUD Layout. From here, you'll be able to move, resize, and customize all the different components of your HUD.

The numbered buttons along the top allow you to create and swap between four different saved layouts, allowing you to create different setups for different contexts. The System, Hotbars, and Duty buttons toggle which UI elements can be modified, and the settings for an individual element can be accessed by selecting the element and clicking the cog icon next to the Current UI Element dropdown menu.
For some elements, this will only contain basic options like toggling visibility, changing size, and adjusting transparency, while for others, these options can be much more customizable. For example, the target bar can be split into three individual components displaying your current target's health, status effects, and ability cast bar separately. This provides you more granular control over your HUD, allowing you to resize and move different aspects of a singular UI element independently from each other.

Other UI elements like your status info and job-specific gauges may also provide enhanced customization options, so be sure to look into the UI Element Settings when you find yourself looking for that extra bit of control over your HUD.
Changing UI Settings
Additional settings for controlling the behavior of your UI can be found within the Character Configuration menu (K by default, or under the System category of the main menu) under UI Settings on the left. Settings for different categories of UI components can be found via the General, HUD, and Party List tabs located at the top of this menu.

These options provide further control over how certain UI elements act, such as customizing the default order of your party list, or the number of quests displayed on your Duty list. Additionally, some settings here allow you to customize aspects of the UI that aren't associated with a specific UI element, such as floating text that appears when you deal damage, or the names displayed over player characters.
Tips for creating an effective UI
When creating your UI, there are some things you should keep in mind to ensure your layout remains coherent and easy to use. For example, think about what types of information are important to you, try to anticipate what UI elements you'll need to quickly find at a moment's notice, and place these elements in locations that are easy to see. You might place your target's cast bar near the center of your screen so you can easily notice when a dangerous attack is incoming, or move job gauges next to your character so tracking them is easier.

Conversely, it can be important to reduce clutter by moving less critical UI elements off to the sides of your screen, or hiding less useful elements completely. Utility hotbars containing shortcuts for mounts, emotes, and menus often make more sense being placed out of the way, and UI elements like the Main Scenario Guide may no longer be necessary after you've finished all the available Main Scenario Quests. Some players may even opt to move all their basic ability hotbars off to the side of the screen to leave more screen real estate for the game world, leaving only critical cooldowns near the center.

Each player's UI and HUD layout settings will be shaped by their own personal needs and preferences. A UI that centralizes all the major combat elements close to the center of the screen might work for players invested in high-end raiding, but at the same time be detrimental for someone more concerned with immersion and roleplaying. There's no one-size-fits-all solution, so don't be afraid of experimenting around with different layouts until you find one that works for you.