Adding to what the other person said about complete proteins, the whole thing is really overblown and frankly almost never something to even begin to worry about. Virtually every plant food contains every essential amino acid, it's just that the ratio of those amino acids is slightly different than the ratios in human or other animal flesh. Notably legumes have marginally less methionine than a lot of other protein sources. But even in an outlandish scenario where you had to live on nothing but beans, this deficiency would still be easily overcome by just... eating a little bit more of the beans..
But people don't do that. They eat lots of things, and many foods supply varying amounts of protein. Despite the hype, there is no need for the average person to worry about their protein intake. If you are eating real food and getting enough calories, you are getting enough protein.