whoever is a pronoun that is used as an indefinite subject. An indefinite subject is used when making a general statement and the specific person or thing being referred to is unknown or unimportant. For example, one might say, 'Whoever arrives first will get the last slice of pizza.' This sentence makes a general statement about the importance of arriving first, without specifying who that might be.
1. Whoever finds the lost item should turn it in to the lost-and-found.
2. Whoever wins the contest will get a free ticket to the concert.
3. I'm not sure who to invite, just invite whoever you think might be interested.
whoever is very versatile and can appear at the start of a sentence, in the middle, or at the end. It should also be noted that the relative pronoun 'who' should be used when referring to a specific person or things that are known or important.