🍊 Is it okay to use Vitamin C serum in the morning?

My skin tone has been looking dull lately, so I'm thinking of trying a Vitamin C serum. I looked it up and found many claims that it helps with whitening and improving skin tone. However, I also saw some posts saying that using it in the morning could irritate the skin due to UV rays, so I'm a bit hesitant.

Does anyone happen to use Vitamin C serum in the morning? If it is okay to use it in the morning, I am also wondering if I absolutely need to apply sunscreen along with it. I would also like to know whether it is better to use it every day or every other day.

Since it's my first time using this, I'm a bit confused about the concentration and the order of application. If you could share any products suitable for beginners or any usage tips, it would be really helpful! 😊