Resignation on probation

No. You do not worry. Whatever the jobs assigned to you by the management, you have to fulfil before you exit. And if any official information kept with you in the form of documents,files etc. handover to the managmenet with smile. And smilely walk out without blaming your management.That is all.The management will issue relinquish certificate from your jobs. 

You have posted that:

--"it is just mentioned that employment can be terminated without any notice or assigning reasons.one month notice period will be applied only after probation period." Thus there is no notice period is applicable to you.

--"After the mail, they are telling me to complete the formals before exit and to face exit interview.if failed to do so i will have to face legal notice from the company." Employee should handover the charge and company property if any under proper acknowledgment. Usually companies have a prescribed form/format for it. It is not mandatory for the employee to attend an exit interview, and there is nothing wrong if you want to oblige the company. It is a HR process and formality and HR may provide you exit form for your feedback and you may submit it and retain a copy.

Some companies accept resignation by email and some insist on resignation by letter under signature by hand.

If company has communicated by email, and you have stopped attending office, you may write back to set a specific and mutually convenient date and time and complete the formality.

Until or unless there are some issued which you have not mentioned there should not be any problem, in handing over the charge. If there are some issues you may post these.

If there are some issues and company can declare you absconding, charge you for having left without completing assignments and handing over the charge and caused loss, block FNF settlement, and trouble you for PF, gratuity, and post adverse comments in reference check............etc