For changing the theme of all your chats and channels, go to the Settings menu > Chats > Default chat theme, and select a theme of your preference. For customising each chat individually, tap on the name of the contact at the top of the chat screen (on iOS), or click the three-dot menu (on Android), and select the "Chat theme" option.

WhatsApp has introduced customizable chat themes and wallpapers, allowing users to personalize their chat experience with colorful bubbles and backgrounds.

Meta-owned WhatsApp has introduced a couple of new features that make the messaging platform more colorful. WhatsApp now has pre-set chat themes and backgrounds, which can be applied to all chats or individual chats.