Picking a major can be simple or complex. In simple terms, pick one that you like but that also emphasizes the relevant skills: technical writing, reading comprehension and analytical reasoning. In a nutshell, you need to have proficiency with usings citations in writing, making sound arguments and having loads of reading. That will give you good skills for law school.
But there is another feature that makes this more complex. Aside from worrying about just the skills, some students are so ambitious that they use “stacking” as a strategy. Stacking is where a major has independent relevance to a particular legal career. Students wanting to be a corporate lawyer, for example, might choose accounting as their major. If they want to be a patent lawyer, they might choose engineering. If they want to work in public health, they might choose a medical field. If they want to sue doctors, perhaps they will have a nursing credential.
There is absolutely nothing wrong with “stacking” – it’s a great thing to do. The only caveat is that most students don’t know what they really want to be at the age when they start a major. And if you do know this, one fear is that something else has produced it (a family encouragement). This can go deeply wrong if it doesn’t then fit who you are and want to be. But it also can be beneficial in some cases.
Point being, stacking is a personal choice. And if you are not doing that, just shoot for skills.