For diploma in civil engineering or any course you just have pass you 10th board exam with 60% minimum.
The eligibility criteria is 10th or 10+2pass minimum average score of 50-60% is expected along with the completion of a secondary board examination in science subjects plusmathematics .

Software you have to learn for better scope
AutoCAD Civil 3D Certified Professiona
Revit Structure Certified Professional
STAT PRO

Roll or career in civil engineering
Structural Engineer
Site Engineer
Construction Engineer
Building planer .

For addmission you can visit this link to see the fees and name of college
https://engineering.careers360.com/colleges/list-of-diploma-in-civil-engineering-colleges-in-india.

For more information in civil engineering you can visit here
https://www.careers360.com/courses/civil-engineering-course

Thank you. All the best. I hope this answer helps you