We can have users to rate the item in Sharepoint application such as custom list, announcement or document library by doing some simple configuration in list/library Setting. 

The ratings can be in the form of Likes or Star Ratings.

Go to list settings on your list and choose rating settings

Choose yes for allow rating and select rating type whether likes or star ratings

The star ratings will allow the ​user to select how many stars they wish to give to the item and Likes allow user to like that item as shown below.