Yes, it's totally fine to wear socks with slip-on shoes. In fact, many people prefer to wear socks with them for a variety of reasons, like comfort, reducing foot sweat and odor, and preventing blisters.
The type of socks you choose can depend on the look you're going for. No-show or low-cut socks are a popular choice as they make you look like you’re rocking bare feet, keeping that minimalistic look that slip-on shoes provide. In the end, your comfort and your styling is the key. If wearing socks with your slip-on shoes makes you more comfortable and feels better, go for it!