The Discord app provides its users with a unique feature called the spoiler tag. Spoilers tags allow users to indicate that a message, part of a message, images, and attachments are spoilers so that others can choose whether to view the message.
Discord users who don't want spoilers tag in their server or who do not wish to use spoilers tag in their Discord channel may disable it from the Settings of the Discord app. Here's how to hide spoilers in Discord.
Open “Discord” > “Default settings” > “Servers I moderate”.