Make adjustments in my website

I need someone who understands very well about html and php and programing languages used in websites. I have a simple selling website that I need to begin using, but can't do that until some adjustments are made there. They are: 1- I need customization to allow the following: for example, if someone wants to buy 2 items of size M of color pink and more 4 of color green of size L or shoes of different colors and sizes in the same order I want it to be possible, since it is a normal function even in any kind of selling websites, even in the simplest ones different from mine and mine does not have it. So, I need customers to have the options to buy any amount of products in any different colors and also in different sizes in the same store in a single buying action. 2- about the thumbnail images when anyone wants to share a link of any products in Facebook or Whatsapp, I need that the website automatically show a little image of the respective product with the link since this is also normal for websites that sell goods and mine does not have it either. I will only answer offers that mention the word "Blue" in the offer, so I will be sure you read all the descriptions.