(a) Yes. You would be eligible for credit of tax paid on
material used for job work.
(b) No. You are not required to raise two different invoices.
You would be raising one invoice similar one to what you
have been doing till now and GST at the applicable rate
will be charged on the invoice value. You can pay your tax
liability by using Input Tax Credit (ITC). However, invoice
should carry all the details as required by the CGST Act,
2017 and the CGST Rules.
(FAQ-10 TEXTILES)