Can I be eligible for the UPSC IAS exam if I have done my graduation in a B.Com external at Saurashtra University?

It is mentioned nowhere that only regular candidates are eligible to appear for the UPSC examinations. IAS stands for Indian Administrative Services, and all you have to do to become an IAS officer is pass the UPSC Civil Services Exam. 

• This exam is divided into two parts: preliminary examination and main examination. 
• You must first pass the preliminary examination before proceeding to the main examination.
• The preliminary examination is objective, and there are two papers in total, both of which you must pass. 
• Only those who pass the preliminary examination are eligible to apply for the mains. 
• To apply for this exam, you must have graduated from a recognized university with a bachelor's degree in any field. 
• Candidates who are in their final year of study are also eligible to take this exam. 
• Your age should be between 21 and 30 years old, with an upper age limit for restricted category candidates.

The notification for the examinations is released every year in February. After the official release of the notification, You can only fill out the application form online. There is no option for candidates to fill out an offline application form.