i would like to check my macbook serial number pls

Here you go -> Identify your iMac model - Apple Support

You can get basic identification of the model by entering your serial number here -> Check Your Service and Support Coverage - Apple Support You will get a reply like "iMac (Retina 5K, 27-inch, Late 2015), the original purchase date and whether or not it is covered by AppleCare.

For further technical details, go to everymac.com and look up your model. Here are the pages for:

• All Macbook models
• All MacBookPro models

It would help us help you if we knew what kind of serial number check you are trying to achieve. Lost/stolen? New/used?