Hi Aspirant!
No, you cannot fill two application forms simultaneously. However, you can fill/apply for multiple courses in a single application only. According to your preferences and eligibility criteria, the one course which suits best will be allotted to you. But if you fill two different application forms for two different colleges and get admission, then your admission will be cancelled from both the colleges. To know more, visit here:

DU Application Form 2021 (Released), UG Registration: Apply Online (careers360.com)

Thankyou!