@abdulbari12032 use the [document|35586] to work on your computer. Page 44 will tell you the type of memory.
4-GB (2133-MHz, DDR4) for computers with Intel processors HP part number 820569-001
8-GB (2133-MHz, DDR4) for computers with Intel processors HP part number 820570-001
16-GB (2133-MHz, DDR4) for mobile workstation HP part number 820571-001
and the amount. It will show you how to change it and how to prepare for it.
While you work on your laptop, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has a device with the same issues as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.
***Repair is War on Entropy!***