Hello,
.
PHD known as Doctor of philosophy which is a higher level of education. Now just like 11th comes after class 10 and degree comes after 12th. PhD comes after masters.
.
It's just a next level of education with various courses offering same like other level of educational levels.
.
Here is the list of level wise education

• 10th
• +2
• degree
• masters
• PHD

Hello.
PhD is a doctor level degree also known as doctor of philosophy student in PhD basically gives their major contribution towards their subject by writing thesis or researching in it.
This is a highest level degree.
For more details you can refer provided link:
https://www.careers360.com/courses/ph-d-doctor-of-philosophy
Best of luck.