Need help with commands

Making a base and there's a moose goose spawn close enough to be a problem

I looked around and it looks you can delete that with commands but I not getting how use this and make work, so if someone wants to give me a little help I appreciate

Details:

Playing on computer, world with caves, using DS alone the mod, playing alone obv, playing on online

When I click the little think by the side of the number 1 to open the command tab (forgot the key name) it's doesn't shows "local or remote" is just doesn't shows nothing

I'm not sure if this is some bug or complications of some mod, but I tried using commands and doesn't work

So if someone could give a little help in that because I knew the game had commands but I'm totally zero on how use them