!prefix clear leaves you without a prefix meaning you have to mention the bot to set a new one. !prefix set <prefix> is most likely a better choice in most cases
By default this is set to ! and ?
|!prefix||--||Lists the prefixes currently in use by the server|
|!prefix add <prefix>||!prefix add "sudo "||Adds a prefix to be used by the bot (limited to 10) NOTE if you want a two word prefix or a prefix with a space after it or an emoji you must use quotes, this is a discord limitation and can't be fixed|
|!prefix set <prefix>||!prefix set "haha "||Sets the specified prefix to be the ONLY prefix in the server|
|!prefix remove <prefix>||!prefix remove !||Removes a prefix, same limits as !prefix add applies here, can't remove mentioning the bot.|
|!prefix clear||--||Removes all prefixes except mentioning the bot. This (obviously) means you need to mention the bot to register more prefixes|