How are invoices uploaded on the GST portal from BUSY? Is it through JSONs or some other method?

In BUSY,there are several methods for generating GSTR E-returns,you can follow these steps:
 Step 1:Go to Display menu,
 Step 2:select Gst reports,
 Step 3:Select Gst return,
 Step 4:Here,you will find all the options to generate returns,GSTR1,GSTR2,GSTR3B,GSTR ITC-4,GSTR-6,GSTR-9(ANNUAL RETURN),All these reports are for viewing purposes,you can check your data in this reports.
 Step 5:The report displayed in the section below is for generating returns,there is a returns to generate GSTR1-e-RETURN,GSTR2 e-RETURN,GSTR3B e-RETURN,ITC-04 e-RETURN, GSTR6 e-RETURN,
 Step 6:You can generate file through JSON, As per government template,CSV and plain excel but only the Gstr1 return can also upload as direct from BUSY.
 Step 7:if you want to genrate GSTR1 click GSTR1 E RETURN window will appears there is many option to generate gstr1 return file,if you wants only create JSON then click JSON tab,Please select the frequency at which you file your documents, whether monthly or quarterly then give path wherever you want to create json file click OK then window will appears to check errors in transactions,errors in hsn and documnet summary check in all then you can click proceed with JSON, your json file will be genrated.then you can upload JSON file mannualy on portal.