Bot sending msg to infomation section of channel directly but it showing channel not found

Question

discord.com/channels/967808235048423484/967808235048423486

Ch-id - first

wnd-id - second //welcome-and-rules

client.channels.fetch('<Id>') .then(channel => console.log(channel.name)) .catch(console.error);

For ch-id //Unknown channel

For wnr-id //shows name welcome-and-rules

client.on('ready',() => {
  const channel = client.channels.cache.get("<id>");
  channel.send('holo');
});

For ch-id //unidentified

For wnr-id //it sends a msg

Another illogical question

Channel has 4 information sections and 2 text channel section

let ch-id is valid

Then what does it do

channel.send('helo');//for ch-id

I mostly saw this using in message event

Not separately

here is my first question for more details

link