Vat registration

Sir,

A new company was opened and the company has touched the threshold limit of Rs. 500000 of turnover.

No VAT is charged on the bills till 5 lakh

Now the company will have to take MVAT registration. This registration will take approx. 5-7 days.

So in the meanwhile can the company issue bills. If yes then whether VAT is to be charged on it or not?

If the VAT is to be charged then what are the guidelines and DO's and DONT's for it??

Kindly guide me on the same???