Your post shows up in the players list and guilds can see you're recruitable.
Click an icon to select it, then click the star to mark it your main.
Silkbind
Bellstrike
Bamboocut
Stonesplit
These are checked against each guild's posted requirements to find guilds you actually qualify for.
Neither of these ever excludes you from a guild's matches — they're shown as a soft signal alongside everything else, since a guild's stated best clear can mask a carried player, and most guild members never personally fight in a Guild War regardless of their guild's league standing.