Hello Saurabh, 

Yes, BHU does have a Diploma course for lab technology at the PG level. To be eligible to apply you need to graduate B.SC with any one of the following subjects: Botany/Zoology/Chemistry/Biotechnology. And you must have an aggregate of at least 50% in your graduation (45% for SC/ST) 

The admission process is like most other colleges, you have to fill up the form and upload relevant details. Once the form is successfully submitted, you will receive further instructions from the college regarding admission. 

I am afraid the application forms are no longer available online. The last date to apply was 16th March 2019 for both UG and PG courses. 

Hope this helps.