The first thing that you're going to need to do is to open the console command menu. Luckily, this is very simple and can be done in Java Edition by opening chat and typing the / key.

Hence, there is a method to clear the chat box in Minecraft. Note that you can only clear chat in the Java Edition.

Minecraft: Java Edition Snapshot 22w24a is now available to testers, with two new features for Minecraft 1.19 "The Wild Update." Allays can now duplicate if given amethyst shards, and player chat ...