Multiple series of GST Invoice

ABC Ltd generally prepared GST Invoice from the Tally software for FY 2020-21, it is done by the Mr.A but due to unavailability of Mr.A, GST Invoice is prepared by the Mr. B Mr. B has no techingal knowledge for invoice creation from the tally , so he prepared invoice from the phyiscal printed GST invoice copy, but the format of printed invoice is not same as tally invoice, series number of such printed invoice is the continuation of tally invoice
Query 1:- ABC Ltd can follow this? Is any restriction in GST law
Query :- we can follow the multiple series number of invoice in the same GST registeration? Is any restriction? When multiple series of GST Invoice is allowed?