invoice tax bill in composition scheme

You have to issue bill of supply in this case.There is no fixed format of invoice in GST law however certain requirments are prescribed as below:

(a) name, address and GSTIN of the supplier;

(b) a consecutive serial number, in one or multiple series, containing alphabets or numerals or special characters -hyphen or dash and slash symbolised as “-” and “/”respectively, and any combination thereof, unique for a financial year;

(c) date of its issue;

(d) name, address and GSTIN or UIN, if registered, of the recipient;

(e) HSN Code of goods or Accounting Code for services;

(f) descripttion of goods or services or both;

(g) value of supply of goods or services or both taking into account discount or abatement, if any; and

(h) signature or digital signature of the supplier or his authorized representative:

Also attached is invoice format for your reference.