Hi Pawan,

You're adding a worksheet per contact in your for loop over the partners. If you move that part outside of the for loop it will add all partners in one single page. You where also setting the format again for every single contact. This should work:

from odoo.addons.report_xlsx.report.report_xlsx import ReportXlsx

class PartnerXlsx(ReportXlsx):
    def generate_xlsx_report(self, workbook, data, partners):
	    report_name = obj.name
        print("REPRTTTTTTT", report_name, report_name[:31])
        # One sheet by partner
        sheet = workbook.add_worksheet(report_name[:31])
        bold = workbook.add_format({'bold': True})
        index = 0
        for obj in partners:
            sheet.write(index, 0, obj.name, bold)
            sheet.write(index, 1, obj.email, bold)
            sheet.write(index, 2, obj.telephone, bold)
            index +=1
PartnerXlsx('report.res.partner.xlsx', 'res.partner')

Note: You're writing on row "0" every time with sheet.write(0). You might want to add an index/counter to the function and use this as I've did in this code.

Regards,
Yenthe