Ok, so I beat Breath of the Wild. I've seen epic mods for the game, but I want to know how you can get mods for the game. If it matters, I play on the Nintendo Switch and I have both DLC. I did a google search and I got no answer. I also want to know if there is any way to search for mods to get them. I've watched a lot of Breath of the Wild mod videos and I really want to know how I could get some of the mods used in them for myself.
You will have to install homebrew on your switch. (Against Nintendo's Terms Of Service) I myself would rather not go into detail about hacking a switch but if you look, You can find guide's on the topic. I'm not saying I recommend modding your switch. But it is an option.
After that, you probably will have to install some homebrew applications and install the mods!
-- again I do not recommend doing this.
TL;DR : You probably can't and/or shouldn't.
BotW mods are generally intended for Cemu emulation of the Wii U version. Some mods can be installed on official hardware through homebrew, but this is tricky and against ToS, as was already said, and I wouldn't recommend it. Modding may not even be possible on your Switch due to it relying on hardware exploits that have been fixed on newly produced units since their discovery.