Questions & Answers about qǐng kàn yǒuxiàoqī.
Here 请 means please. It makes the sentence sound like a polite instruction or request.
So:
- 请看 = please look / please check
Be careful: 请 can also mean to invite or to treat someone in other contexts, but in this sentence it is just the polite please before a verb.
Chinese often leaves out the subject when it is obvious from context.
In a notice, label, or instruction, 请看有效期 naturally means something like:
- Please check the expiration date
- Please look at the validity period
Adding 你 would usually sound unnecessary here. Short instructions in Chinese are often very compact.